IMO React is popular because it forces people to understand MVC. I've actually never seen a Backbone app where views render based on the model. It's too easy to just ram in jQuery in the render function. A lot of new frameworks just try to reduce Backbone's boilerplate of manual model-view event binding in different ways, dirty watching, virtual DOM, etc...

Even flux is basically organized pub/sub. Instead of shouting out what you're doing, you're logging your actions in a logbook. Also, instead of arbitrary actions, you can only combine certain pre-approved actions. It's a natural extension from using globals (too messy) to shouting out your intent while basically using globals (too noisy, still kinda messy) to what I've described above. (still kinda messy, but can be traced and unit tested easily)

Flux/Redux and whatever still doesn't help you solve problems that truly reduce complexity like how to organize scope or what abstractions to use.

There are tons of good frameworks out there, and it's rather disappointing to me that people don't realize that the basics are the same and insist on everyone jumping on the same bandwagon (that just happens to be supported by a rich large company).

Not really "binding" per se -- mostly because "binding" implies you're attaching events to objects and thinking about "changes", and object lifecycle is still something you're concerned with.

React is more functional in nature -- A react component is, almost entirely, a function that takes arguments and spits out DOM elements. React then diffs the desired DOM with the current DOM, and computes the set of transformations needed to update the UI to match the new state -- i.e. "Add a few rows to the table, change the text in a particular span equal to 'boom'" or whatnot.

Data binding exactly, like binding a declarative formula in Excel. Not like Backbone, which did event binding, invoking the programmer's code to imperatively update the DOM.

Knockout, and Angular, both do data binding, but their implementations fall short on complex application state changes & how it translates to DOM changes--leading to incidental complexity: digest loop, TTL, $watch, observable, custom handlers.

React stupidly doesn't try to understand how the state changes translates DOM changes, and instead rerenders, diffs, and applies the update. React's declarative model is also why it can render on the server side, iOS, or Android.

Still, React doesn't translate list sorting to DOM changes efficiently, so imperatively optimizing is still sometimes needed, but less often than in Angular & thankfully not complected by the DOM. React will be replaced when someone solves this. Most likely needing a new programming language, to analyze the application logic & automatically translate into efficient UI updates.