I am working on creating a web app now and for some reason decided to learn Dart and AngularDart at the same and do it with these technologies and it's close to being nightmarish. There are way too many concepts and things that tie together sort-of magically -- all to get a few form fields on a screen. I wonder how people come back to fix issues or add features in their Angular app after a few months away from it.

That said, I think, for bigger groups/companies working on a complex product, I can see that Angular ensures a certain level of "architecture" and code organized correctly instead of being coded to each dev's personal style.

But way too complex for single-person apps or for simple SPAs.

All that to say Angular is less popular because it is too complex to learn and use quickly.