React isn't "new". It was deployed on FB in 2011, and open sourced in 2013. (2006 for jQuery). 4-5 years is plenty of time to develop a rich ecosystem of libraries ... just recall jQuery circa 2010-2011.

I certainly wouldn't want to build a mobile app these days with jQuery, since that would generally mean more of a pure Cordova app. (I do think that Ionic however would be a great option depending on the use case)