I agree when you’re talking about the most well known of plugins and so on, but IME for application code all that goes out the window. A lot of developers really didn’t know how to write JavaScript back then. Still don’t, but we didn’t then either ;)
I agree that the library has great convention. I actually learned quite a bit from that API when I was starting out. The only problem was you could really abuse the usage of the API.
I'm realizing now that this isn't a fair comparison. React 'wins' here largely because it has a smaller scope. It's for giving functionality to templates built in the library using a certain approach. jQuery was far more open ended and far less opinionated. That was as much it's strength as it's weakness.
It's definitely not a direct comparison. But I do think react is a nice safe tool for larger teams.