> They want sites that work quickly, are easy to understand, and work on mobile just as well as on a desktop.
Not quite: users want to achieve specific tasks as quickly and easily as possible. Certainly "work quickly" and "work on mobile" are two huge pillars of that for many (probably the majority of) tasks, but for many applications you have to make significant trade-offs in functionality under the constraints of a static site.
Anything built on the web is competing with something that already is or can be built natively. Native applications don't have to concern themselves with this sort of limitation on interactivity as a trade-off for latency, which is an advantage. On the other hand, the web has the (huge) advantages of open discoverability and no-install distribution. It makes sense for both platforms to be working to fill in their gaps while trying to minimize the trade-offs.
It's clear that slow startup due to big chunks of js (and media) on load has become a big problem, and people are working on that, perhaps without much to show for it yet, but it isn't obvious to me that ceding the territory of interactive applications back to native implementations would be the better way forward.