[TheLoneWolfling]

Then you end up with the question of "how do you decide what libraries to include"

[bduerst]

Exactly.

Then you create an entirely new, fragmented ecosystem like the current html and css web standards, adding more complexity and layers to front-end web development.

Best that the browsers stay agnostic in that regard.

[benologist]

http://trends.builtwith.com/javascript

All the browser companies are in a particularly good position to collect this information too.