That is in part due to the complexity of problems in frontend and that most companies don't need to solve those problems (or don't have the resources to solve them).

Ember would be a notable counter-example.

I think a more important reason would be that Facebook/Microsoft/Google media influence and corporate support creates massive brand awareness and generates instant interest. Educational projects anticipate the interest from developers and create courses, tutorials and reviews. The cycle continues and bam! we have an information cascade[0].

Rich get richer and poorer get poorer (in developer mindshare). Megacorps reap the benefits while indie developers are not able to achieve critical mass.

I shudder when I think about the possible Typescript/Microsoft, Angular/Google, React/Facebook domination in web technologies.

[0] http://en.wikipedia.org/wiki/Information_cascade

I think that has more to do with developer evangelists/pr people and budgets. Most good ideas languish in obscurity, even when given the light of day.