I've used React extensively and you're almost forced to use it if you want to be hired anywhere (I'm talking front-end development).
The trend nowadays seems to be to adopt any framework that huge companies use thinking that it'll be good for you. Honestly, do we really need all the complexity of the what the biggest social network in the world uses, to build a project 1/1000 the size?
I'm sticking to PHP/MySQL because I'm productive with them, I build small apps used by 10-20 employees at the most, I don't need NoSQL to scale horizontally to million of users and don't really need Node since it doesn't really matter if it's real time and PHP is found on every hosting platform—including the one all my clients have been using for years. I currently use React but all I do is CRUD operations and some visual effects, I'm thinking about moving to web components to lose Webpack, Redux, Babel, and a 200MB installation to save 100-200 orders/week on a database.
At work I have written a couple of CGI scripts in Perl, because that was the easiest, fastest way to get a working solution to a relatively small problem. I know CGI is totally '90s, and Perl has not been hip for at least a decade, but damn it, it gets the job done quickly without fuss.
I kind of suspect that with PHP the situation is comparable to Perl - you have a well-tuned, mature interpreter, a rich library ecosystem for almost any task you can think of, and a community of experienced developers.
PHP isn't perfect at all, with all its inconsistencies and counterintuitive constructs, but it works great. Lots of libraries you can install with Composer, most people know at least some PHP.
On top of that, unless WordPress isn't rewritten in a new language (which won't happen) PHP won't go anywhere.
Perl is fine, too. We solve problems for clients who pay us to get the job done, not be brag about how we use the latest, coolest technology.