That’s exactly the problem. Sony has nearly no high quality lenses that are actually small.
Apart from the entire Batis range.
In that regard I think Nikon is the first company actually doing the right thing with their small but amazing lenses.
I don’t mind it the other way around, but most companies produce great 2.8 zooms, but there f4 versions suck.
If I ever would buy such a camera it would have to be light and small with a good range.
By prioritising small size over other factors, you're already accepting compromises in performance which wouldn't have to be made if the size/weight restriction weren't there. A slower, smaller lens that matches the optical performance and build quality of a faster lens with no such size restriction isn't likely to be much cheaper than the faster lens.
Besides, making the initial lens lineup small and light rather than fast and with no compromises locks out large swathes of high-end users, at the very time in the product cycle you want to be locking in these users making long-term investments in a new system. With f/4 zooms in the 24-200mm range and slowish primes (by prime standards), they'd preclude most photojournalists, event photographers, wedding photographers, portrait photographers and many other groups from choosing them almost completely. Anyone who wants/needs strong subject isolation is never going to choose a slow lens, no matter how sharp or light. These photographers would likely go and buy another mirrorless system that offered them the fast lenses and never look back, even if Panasonic/Nikon/whoever later caught up and offered similar lenses. Nikon discovered this, to its detriment, when it was slow out of the gate with CMOS and high ISO, and slow again with full frame - they later caught up and surpassed Canon performance-wise, but never regained the market share with DSLR that they had in the film days. Essentially, they'd be left with cashed-up amateur landscape photographers and soccer mums/dads, which, while a lucrative market in its own right, is never going to have the star power of higher-end users that is so valuable for advertising and brand promotion. Witness Canon's big white lenses at sporting events and in press galleries for an example.
Sure, it's great to have a strong suite of smaller/lighter, but still super-sharp, lenses for this market, but it can't come at the expense of the larger, pro-grade (utility-wise) lenses which are the poster-boys, if not necessarily the cash cows, of your brand. Many photographers would probably end up using a combination of the two - sharp and lightweight 14-24/4, 24-70/4 and 100-400/4.5-5.6 lenses ('lightweight' being a relative term in the last case) would make for a great portable kit if combined with a fast 35/50/85/1.2, 105/1.4 or 135/1.8 prime to cover the portrait focal lengths where you really want the subject isolation only a fast lens can bring. You'd then have lightweight, slower but still super-sharp lenses from 14-400mm (560mm with a 1.4x TC) for subjects where you want everything in focus, as well as a fast lens for those focal lengths where you tend to really need background blur, but would have a hard time getting it with a slower lens. But it's not the slow, lightweight lenses which build the brand - it's the large, fast lenses seen in the hands of pros shooting news, sports and events.
