To play devil's advocate for a bit, what you said applies to jQuery as well. It has an enormous plugin ecosystem. I know, I know, people are going to now start pointing out how X or Y specific thing is "better" in React, but then isn't bundle size, application space code conciseness, etc also W and Z specific things?

At what point is the argument for one toolchain over another simply circular reasoning / backpatting? Trade-off analysis isn't just pointing at X, it's about looking at the balance of X and Y vs W and Z.