This is actually a big factor in why web apps have the perception of being bloated. Basic widgets being missing means that everybody and their dog has their own custom implementations, nearly all of which are somewhat slapdash in nature due to speed of implementation being prioritized over quality. They never meaningfully improve either since there’s little sharing of efforts, with everybody instead preferring to reinvent wheels for themselves.
If the platform provided a more robust set of widgets, much of these problems would go away since devs would be using those instead either as-is or with light cosmetic customizations. Over time the browser implementations would get better and all users would benefit with more performant, less buggy apps.
> […] pick the one that’s already winning and make it the best we can.
I agree, it can be much better. Tons of incremental improvements have been made, and should continue being made.
I too would like to see browser close the gap completely, supporting everything needed to build real applications, not hacked together applications that accidentally work. We seem so close…
The main problem I think is what you have identified: we need sophisticated composable widgets with practical and sensible defaults, that are also really customizable with scoped CSS, built right into the browser. This alone would be the biggest QOL improvement as far as web development goes, in several generations. I really don't know why this is not the highest priority for the W3C