React isn't that simple. You still have all the package manager/transpiler/build baggage. You still sacrifice pages that aren't blank if javascript is disabled of fails and all the potential SEO/accessibility costs of that.
And you suddenly end up with great globs of javascript in a page that might not need it.
I guess what I really meant to say is that you could levy the exact same concerns on many other libraries / frameworks. None of that is specific to React.
I guess I was also assuming that if the OP was considering using React in the first place, that they were doing more with jQuery than just minor interactivity improvements. But I suppose your concerns are valid if that assumption isn't true. I'm thinking app, not blog.
Maybe he was but I do worry that anyone new to front-end is being pushed towards frameworks rather than being told to start with the simplest approach possible.
I saw a comment from someone a few weeks ago who knew angular but had never used jQuery. I was rather baffled how that had come to pass!
And you suddenly end up with great globs of javascript in a page that might not need it.