Ember.js was created by big names in the rails community, and made big promises of being a rails like batteries included all in one framework.
There's a reason it didn't really get the popularity the other frameworks got.
There's a reason it didn't really get the popularity the other frameworks got.
Seems like wycats is interested renewing his Ember work as of late.
I recall evaluating Ember right around the time they switched from their last pretelease of I think 1.0 and suddenly all the documentation was either gone or out of date and not applicable. I ended up going with AngularJS (1.23 maybe?) and didn't look back until I went to work somewhere that used ember exclusively. It was far less pleasant to use than anything else I had been using up to that point except maybe Backbone.
There's been a few additions to the JS core APIs like webgpu and a few others, but all of them have been extremely niche. There's not much that's been added since 2016 or so that you couldn't pick up in a heartbeat, so it really boils down to the frameworks themselves. Ember lost to AngularJS, then Angular and React.
Basically, if Ember.js used abstractions that were better for, say, extremely complex applications, it was dead in the water, because most applications make their library decisions when they are small and relatively straightforward. The market for javascript top-to-bottom rewrites of extremely complex apps (where something with those more complicated abstractions shine) wasn't really large enough for it to become dominant.
I also found it difficult to reason with, even though I'm an experienced Rails developer used to spooky action at a distance in the framework. Something about troubleshooting on the frontend really made it more difficult.
Circa 2010 those people who were so successful with Ruby had come to the conclusion that they couldn't sell RoR apps anymore so instead they were struggling with Angular -- not to do anything they couldn't with do Rails but rather they though customers demanded applications that looked like Angular applications.
React was a big hit because it was an "Angular" which people could actually deliver working applications with. Its strength I think it is that it addressed certain concerns but left other ones unaddressed such as the theory of async comm. If there is a simple mapping between the state of the application and the state that is represented in the React tree life is great but I look back at the applications I was writing in 2006 and it still looks like a regression.
What I like about it is that I can draw absolutely anything I can imagine with it, even 3-d virtual worlds
Vue has a model which is closer to my mental model of web forms with first-class lists but I can see how to get into "you can't get here from there" situations.
I see the problem React solving is "how to compose an application out of components" and compared to WPF, JavaFX, and such, it's dramatically simpler, it's like a missing chapter out of Graham's On Lisp
Edit: and yes, as you said, it came from Facebook, so it wasn't just a solo developer's grad project; it had a large amount of support right out of the gate.
I am not a UI developer and just needed to understand/debug something, it was not easy at all.
React could be introduced only where it was needed, but Emberjs really wanted to be everywhere and in control of everything.