Comment by vkou
JQuery has plenty of good functionality, but you're going to have a really bad time building non-trivial applications as a team if that's all you are using.
Because it's just a library, not an opinionated framework, keeping everything consistent across a development team of varied tenure and experience levels will be a herculean effort.
And yet people do it, and have no problems doing it - I know this for a fact as one project I work on is built on jQuery with a team of several developers. We do just fine with our medium-level non-trivial applications. React really doesn't make things that much easier, and often complicates things that should be simple. Just like with React, it entirely depends on how you approach building the thing. You can certainly fuck up a simple React project too.