I think now is not as critical to have Indexable Site / SEO as it was before.
Before there was pretty much only one marketing channel, Google, and you had to make your site indexable. But now, it's Mobile, Social Media, App Stores, Messengers etc. So while the Google and SEO, wile very important, is not the only channel anymore. As for slaying JavaScript... I don't know anything better and more productive for Web Dev than TS & Svelte. So, even if it would be possible to slay JavaScript, currently there's just nothing better, so slaying JS makes no much sense.
