tech teams certainly aren't going to voluntarily make their jobs harder without word coming down from above

SourceHut does this. It's not a categorical impossibility, but I agree devs are generally going to be inclined to continue with 'business as usual'.

Does it really make dev work that much harder though? I'm not really qualified to comment. Presumably it's going to simplify things in at least some ways.

do your company a favor - educate those in charge about how much page load time matters.

There you have it - the people making the case for less JavaScript may be the devs themselves.