We would still have a framework of the week like we do today. There was a new framework weekly before React and there are frameworks of the week after React. React just gave us one more way of showing text on a screen.
In 2015 I was teaching that React was a lightweight library that simply did function state -> html, codebases were bug-free, snappy and easy to understand. And it was true compared to configuring jQuery listeners the unperformant way into a Rube Goldberg machine of cause and effect.
Maybe I'm exaggerating slightly, but I think we should judge frameworks compared to what other things existed at the time.
It's, by the way, another example of how the only good thing Facebook did was deny Google complete dominance.