Yes, all libs give you vendor lock-in, which means unless Next is a particularly egregious example, there's not much point calling it out as a particular wart. My argument is that it's closer to the opposite, because as far as web frameworks go, Next does this better than most -- very little of the code you write is different just because you're using Next, your code is just normal React code. This is a huge contrast to something like Gatsby, where the lock-in is much stronger.

Sorry but I disagree. Just take any of your a bit bigger React projects and transform them to Next or the way around. In. One. Hour. And production-ready please. Good luck, man (this is vendor lock-in).

If your threshold for vendor lock-in is one hour, there's no point discussing this. But I could probably do it in a day or two, which is good enough in my mind.

I actually just did this a couple days ago (from Razzle to Next), took around two hours mostly fiddling with updated dependencies. Will take longer for a complex app but the lock-in is way weaker than traditional frameworks.