I had a friend who shot a bull moose and had the head mounted. When it was done, he found that the mount was so large in all three axis that he couldn't get it through his apartment door.
This is a metaphor for what I think is a major consideration in a super-zoom purchase, that Michael didn't touch upon. The whole argument for a super-zoom is that you have a do-it-all camera. But when would any of us (photo enthusiasts) want a super-zoom? Almost always, I'd suggest, as a second camera that would be used in traveling, when you didn't want to haul along a whole system. Lens qualities and sensor qualities aside, a major problem with a super-zoom is that it doesn't pack easily, because it's too large in all three dimensions, just like the moose head. If I'm traveling by air, I don't want to put it in a checked bag, because so much stuff gets stolen. And more and more airline trips are on those small jets where they won't even let you take a wheeled bag on board -- you've got to gate check it. So, the super-zoom will have to go in your briefcase or backpack. And they just don't fit very well, because they're too big in all three dimensions. I think the solution to this (in my case, anyway) is an m4/3 camera with a 14-140 (28-280.) With the lens detached, the lens becomes the widest thing you're packing -- the camera body itself, even with an enthusiast body, is quite small. The Sony Alpha system offers the same qualities, with an even larger sensor, at a bit more cost. (You could get a Panasonic GX7 and the 14-140 for about $1100, or a Sony Alpha with an 18-200 for about $1450. In both cases, the sensor and the controls are probably superior to anything you'd get in a fixed super-zoom.) Neither of these options is larger than the best-regarded super-zooms; in fact, I think they might be a bit smaller. An additional argument for this solution, of course, is that you could buy more specialty lenses for the system. Still, neither the m4/3 or the Sony system offers what I'd call a real super-zoom, which would go from a wide (~24) to a long zoom (400 or longer.) If either Panasonic or Olympus offered such a lens, I think it could make super-zooms somewhat obsolete, especially for enthusiasts.
I don't think the RX100 IV comes into this argument, because it's a very short zoom (only goes out to 70mm) although it's great for travel, of course -- the ultimate in flatness.
You might ask, why not just buy a pack that fits the super-zoom better? Well, that can be a problem if you take along a laptop, books and magazines, pens and pencils, extra glasses, etc. Most of those things are thin, and most backpacks that are designed for things are thin, but may be wide and long, and for smaller items. (Think a laptop or a legal pad.) After a lot of research, I bought what I think is one of the best "office" style backpacks, and it works wonderfully for me - easy to carry, takes a lot of stuff, balances well on roller bags, etc. But, a camera with an attached longer lens just doesn't fit.
