[apotheon]

If you're basically building everything from scratch, of course you aren't going to see the churn as much.

If you build on others' frameworks, and those frameworks drop out of maintenance because the maintainers moved on to shiny new things, any security vulnerabilities or emerging incompatibilities with browsers can quickly prove ruinous for people who used those frameworks.

I wrote a SPA while working at a consultancy. It was actually pretty churn-proof the way I wrote it, but during one vacation day and the following weekend a couple people (including the boss) just rewrote the whole thing to use more faddish framework stuff. I don't work there any longer, but since then (about 2016) they've probably had to effectively rewrite it twice if they kept up with that approach.

That's what I mean by "constantly impending obsolescence".