Yes.
> Every three months might be too often for a tool like curl.
Why should a tool for creating dynamic HTML be held to a lesser standard? I wouldn't expect the level of stability that curl has yet, but I would expect it to be an eventual goal of the project. The reason why we build abstractions is so we can eventually stop worrying about a problem; that can't happen without stability.
> You might want to ask a few people who use React to draw the conclusions. I talk to a lot of people in the React ecosystem, and so far the feedback I heard is that updating React has been the least of their worries, compared to some other libraries in the ecosystem which are far less stable.
That's because you talk to other enthusiasts who are happy about changes. Try asking people outside of the React Slack channel for a wider perspective.
I've had people complain on my projects about upgrading apps using APIs deprecated 2 or 3 years prior. And I feel genuinely bad about it, because if they are having to justify spending 3 or 4 days refactoring their app (which is hard to do in a lot of companies) because I made an API mistake 3 years ago... I feel bad about it. We should strive for better stability.