It clicked for me this morning: the thing that sucks about frontend's lost decade's and the obsession with remaking every blog and marketing microsite as "an SPA" (dragging MBs of JS in tow) is the same thing that sucked about Java Applets.
You can promise "richness" and "app-like UI" all day, but if the experience sucks in point of fact, then you're just gonna nerf your own ecosystem's potential.
The shame of the JS-industrial-complex is that the ecosystem they're doing it to is the web.