Ember Engines :)

It's not being used more for the same reason Ruby on Rails is not used more.

Both are batteries included frameworks, with a much steeper learning curve than e.g.

<script src="https://cdn.com/vue.js">

Plus people like to tinker and wire up things together themselves, like router, rendering, state management, testing, etc. That's more exciting than `ember new project`.

I was like that 10 years ago too, but now when I learned the ropes I just want to focus on shipping and providing value, rather than wasting my life wiring up 17 javascript packages of the month together.