I downvoted this because these are (in my opinion) entirely theoretical and not practical answers. This reminds me of the "React is better than Angular(js) because look how compact and clean the API is compared to Angular!" type arguments. This implies that "React apps" are going to be less complex than Angularjs apps but the reality is anything but: large React applications tend to be just as heavyweight and hard to understand as Angular ones once you need a router, state manager, and 20 or 30 other "compact" libraries to do what you're trying to do.

Likewise "When you have a stable component boundary you can upgrade libraries a component at a time, rather than needing to upgrade the whole application at once. Yes, you might have some overhead during the transition" I'll believe this when I see it, but I suspect you're making this sound way less painful than it actually would be. More likely each dev adds a new framework, they all move on to other teams/companies, no one is interested in painstakingly updating everything, and you have perpetual lock-in until you do the "JavaScript Shuffle" i.e. scrap it and rewrite in a new framework.

I'd love what you're saying to be true but my experiences tell me it probably is not.