I never understood why React became so popular.
I thought it was a kind of mass hysteria. I was exposed to a broad range of front end frameworks early in my career (Backbone, SproutCore, JavaScriptMVC/CanJS, AngularJS), one of my colleagues was experimenting with Google's PolymerJS and recommended it. After trying it out, I was blown away by its elegance and simplicity. Yet somehow it never caught on. When React came out, people jumped on the bandwagon en mass; most of them had never even heard of Polymer.
React had some obvious red flags; it seemed unwise to re-render entire components each time and regenerate the DOM instead of trying to work with it; it's a hack. It's not difficult to think of scenarios were it fails; for example think of what happens to an element's scroll bar after it has been re-rendered from scratch; it resets... Yet people kept coming up with workaround after workaround to all these kinds of issues. If they had tried PolymerJS (which was going for a native Web Components approach and interfaced nicely with the DOM instead of bypassing it), they would have questioned React's merits. When the useEffects hook was introduced in React, to me, that was a vindication of Polymer's stance (which it had figured out years earlier) that you couldn't completely pretend that DOM elements don't exist, yet React's solution was not as elegant as Polymer's as it was tacked on as an afterthought rather than as a carefully thought out design decision.
Nowadays, with native Web Components (HTMLElement) in most browsers, I don't see why people would still start projects with React, especially given the massive number of dependencies it typically introduces and how often they keep changing stuff and breaking compatibility.
They promised a simple component library which would be the answer to our prayers. What we got instead is a 7 year religious pilgrimage which involved a million developers simultaneously trying to make sense of it; attempting to discover its true form by inventing abstraction upon abstraction and growing increasingly fanatical as it devolved into a wicked monstrosity which should have brought the wiser among us to our knees, begging for JQuery.