Depends on what you need. If you are building a web application with complicated UX needs (protip: you probably aren't) and/or the team insists on React, you probably need React. If you want an easy time getting a job in the Bay Area right now, you probably need React. If you want to avoid having your comments downvoted on HN, you probably need React.
Citation needed. HN has this really strange assumption that everyone who talks about web technology is working on Wordpress sites or implements TodoMVC for a living.
It's a 3.5 year old framework. Unless your career is "technical cofounder" with 6 month intervals, you probably don't get to pick your stack. People that have up and chosen React for their professional platform and have their company succeed aren't going to be all that common[0]. Within those that have, people who have used it for long enough (and large enough) to burn their hand on the stove are few and far between. Remember when Angular was the golden child and could do no wrong? It's 6 years old now, and took a while before the fandom died down and you could actually find the practical criticism.
I think the assumption that everyone does a 'Todo' is definitely a poor one, but I feel like 90% of the React articles are by people that have used it for 6 months at most, company blogs included. Glancing at the angular builtwith stats[1], they had 600/10k within 4 years. 3.5 years into React and it hasn't broken 100. While these numbers don't directly translate into "complex UI", they are still indicative of long term usage, going back to my hand-on-stove comment.
Whats the threshold for "complicated UX needs"? I'd think for all but the very most basic bootstrap landing page (IE, if any of the value of your business other than a sales sheet is in your webapp) you'd want to use decent tools.
I have a lot to say on this topic, but suffice to say I think the decent tools being used today are far more complex than is necessary for building most web UIs that I deal with.
Yes.
Is it here to stay?
Yes.
Should I get into it?
Depends on what you need. If you are building a web application with complicated UX needs (protip: you probably aren't) and/or the team insists on React, you probably need React. If you want an easy time getting a job in the Bay Area right now, you probably need React. If you want to avoid having your comments downvoted on HN, you probably need React.
So, it depends.