I think once you're invested into an ecosystem you become naturally disincentivized to see another one supercede it.

Honestly I think these discussions are just pretty low quality. I find that people are pretty good at mis-attributing their success and failures to their tech stacks, especially in a field where there's a lot of novices like front-end development.

I've seen a lot of negativity towards Vue from React users pretty much since it started gaining actual usage by big companies. Never by the core React team, just the users of it. To a lesser degree, I've seen some Vue users express haughtiness because they see Vue as much less complicated.