> Armchair defeatist here: Browsers are huge, complicated beasts, the standards are a constant moving target, and websites won't uphold standards.

I think that's the irony here, the standards are pretty much set in stone and just incrementally grow. Some old cruft is beyond obsolete though. On the other hand nobody uses most of the bleeding edge APIs. But JS (and the part that is actually in use) is indeed growing at a solid pace.