So are you saying all the manufactures have it wrong...that f4 zooms are aimed at the consumer market and f2.8 zooms at the professional market? You do know the f4 zooms far outsell the f2.8 zooms right...so I'm thinking the huge consumer market is buying up the f4 zooms just the way they sit. Do you really think they would buy a slightly better lens for say 1.5x the price of the existing f4 zooms? I know that answer and it is no way.
Take away the 24-105/4 and 24-70/4 kit lenses and it looks a lot more even.
And, yes, they have it wrong. It was right for 1990, when everyone had cameras, and has held on as a legacy. For 2020, it's completely wrong. Big Japanese companies are often slow to change direction.
The camera market is changing. The pro market is as small as it's ever been, while the consumer market is drying up, due to a combination of phone cameras, stagnant incomes, a preference for waterproof/shockproof 'action' cameras and technology reaching the point of 'good enough' for many people. The money isn't in selling cheap lenses to the masses, but in selling better and more task-appropriate lenses to high-end enthusiasts. Less volume, but more profit per unit sold.
The low end will stay (as kit lenses and for casual users who just want a camera and basic lens that covers the focal length needed) but the mid grade is dead. It's either low-end or high-end, with little role for anything in the middle. Photo enthusiasts will go for the high-end gear - they're buying the f/2.8 zooms now, since that's what's available, but would equally go for high-quality f/4 zooms which fit better with what they are doing. Beginners/mum-and-dad photographers will go for the kit lenses, not wanting to spend any more. But no-one gets excited about the release of a new, mid-grade 24-70/4 or 70-200/4 - too expensive for non-enthusiasts, while not capable enough for enthusiasts if it doesn't beat the optical performance of he f/2.8 zooms.
I think you just have to be happy with either using a consumer grade f4 zoom ( I do for landscape at times and it's great at f8 ) or use faster primes ( I do when traveling ) or just bite the bullet and get yourself a 2.8 zoom where not only do you get a faster lens...you get better image quality.
The only reason you get better image quality with f/2.8 zooms is because most f/4 zooms are built to be cheap, not good.
There's nothing inherent about f/4 zooms that means they have to be poorer than f/2.8 zooms. Design them with the same care and price point in mind and the f/4 versions will be sharper. Smaller aperture means fewer compromises needed to achieve the aperture, which generally means sharper. Ito also means smaller elements, which are easier to manufacture precisely and without flaws, for better quality and less copy-to-copy variation.
I used to carry a f/2.8 zoom trinity. Most of it was dead weight . The 70-200 would occasionally be used for a portrait, but, the rest of the time, it was like the equivalent of putting rocks in your pack - good for exercise, but adding no useful capability. Had the f/4 zooms been equally good, I'd have used them instead, and thrown in a f/1.x prime for portraits (or just had my macro lens do double duty).
I currently use a 24-70/2.8. It's sharp (after going through several copies), but not prime sharp. If it had a smaller aperture and zoom range, it could have been made even sharper, equalling primes in the f/5.6-f/11 range.
Due to the nature of the Sony lens lineup, I've been able to get away without other f/2.8 zooms adding dead weight. The 100-400 is sharper than the 70-200/2.8 (at landscape/wildlife distances - I've seen/heard that the 70-200 GM is super sharp at portrait distances, but loses out at infinity, a bit like the 90mm macro) so suits me just fine - one lens covers all my (non-wildlife) telephoto needs. Add in a prime for subject isolation when needed, or just use the macro for that.
I'm also using a 12-24/4. It's in the odd position of being as sharp as anything else in that focal length range, and that includes the Voigtlander primes - anything sharper doesn't reach 12mm. But I have no doubt it could be even sharper, particularly in the corners, if it didn't have so ambitious a focal length range - 2x zoom is a lot at UWA focal lengths. This is a case of using a consumer-grade lens because there's actually no better lens out there at the moment. I'll be keeping a close eye on the 12-24/2.8 GM when it comes out, to see if it adds image quality, or just weight and a wider aperture, but have no doubt that, had they gone for a smaller aperture and zoom range, with the same price target, they could make it even sharper.
I also think you have it wrong when you think these other professional photography niches use f4 zooms extensively. Architecture use TSE lenses in order to handle distortion. Studio photographers use high quality primes as their goal is utmost quality in the images. Portrait photographers either use 2.8 zooms or primes. It's really hard to say any photography profession utilizes predominate f4 zooms as their staple.
I never said that other pros use f/4 zooms. Most don't, because the ones available are mostly average at best. But 'don't' is different from 'won't'. They 'don't' use f/4 zooms because current f/4 zooms are no good. That doesn't mean they 'won't', were good f/4 zooms available.
It's a bit like how pro photographers (and high-end amateurs) didn't used to shoot Sigma or Tamron lenses (let alone other brands like Samyang). Their products were shoddy in some way (IQ or AF), so they didn't use them. The moment they lifted their game, they suddenly got a second look, and, now, they're rather popular.
Again, it's a self-fulfilling prophecy. Make the f/2.8 zooms good and the f/4 zooms cheap, but shoddy, and anyone who cares about the quality of their work has to get the f/2.8 version, even if they never use it wide-open. That's why it looks like so many pros use the f/2.8 versions - not because they're using it at f/2.8 (obviously event/wedding/news photographers are) but because there's no decent alternative.
Although you'd be surprised at what a lot of studio portrait photographers use. Most aren't shooting Rodenstock lenses on Phase One backs - that's commercial photographers shooting advertising campaigns, who often don't buy/own their own gear anyway. Instead, all their money's in the lighting equipment, since that's what most influences their image quality. Lenses and bodies are often the cheapest thing that will do the job - and that can mean really cheap. Bodies may be several generations old - they're shooting nonmoving subjects stopped down, with a deep DOF, so AF isn't an issue, and they're shooting at base ISO, so light sensitivity isn't an issue either. Lenses can be really cheap too. Corner sharpness doesn't matter when you're shooting portraits, and corners will usually be out of focus anyway. Wide aperture isn't needed when you're shooting stopped down and using flash. Zoom is great because you don't need to keep changing lenses during a shoot. Hence the popularity of the Canon 24-105/4 kit lens (now that the supply of the old 28-105s has dried up). Better to spend your gear budget on a Broncolor Para, which actually does affect your image quality (or, if you already own a parabolic reflector, saves you time by being much faster to set up and take down), faster IT systems to speed up your workflow or extra backdrops and props to add to your shots. Or, even better, realise that you don't actually need to spend that money to do the job and spend it on beer instead - you can do a lot with a few umbrellas and light stands, and they're much easier to bring to location shoots than large softboxes, and far quicker to set up or take down.
You're describing the situation as it is - f/2.8 zooms are good, f/4 zooms are shonky, so anyone who cares about output quality uses the f/2.8 version, whether they need f/2.8 or not. I, and others, are describing it as it could be - make f/2.8 and f/4 zooms equally good (at the same price point, this would mean f/4 zooms being sharper and better-corrected than f/2.8 versions) and you'd get a spread, with those needing the speed going for f/2.8, while those travelling light or after the sharpest option going for the f/4.
Besides, what pros (at least the most visible ones) use doesn't matter. Amateurs have the money and are buying most of the gear. Pros will get the cheapest thing that does the job, to maximise profit, and will have a smaller collection of lenses, since they're mostly only shooting one thing. f/2.8 are a photojournalist's tool - and probably the best thing for photojournalism and weddings. For anything else, they're an ill fit, often forced into the role due to lack of high-quality alternatives.
