Also, only Dart and AtScript are attempts to overhaul/replace JS, Angular is just a library (with versions for JS and Dart), not attempt to overhaul JS.
How? I mean, if they deleted JS from Chrome in favor of Dart (but not AtScript, which is a JS superset) it might break toolchains that developers use, but making Dart (with dart2js) and AtScript available doesn't break anything.
Do we really want to be stuck with a mostly stagnant JavaScript forever? Ugh.
I hate this part about Mozilla and Apple. I dont have qualms about javascript. It has its good parts and as a full time javascript contractor I earn my living with javascript. But... I dont really want the next generation of developers to be stuck with whatever we have today. I am not in favor of "Here is what you get - do all your innovations inside this box" mentality. Yes, there is scope for improving javascript or ECMAscript but there are limits to this. As Peter Thiel says in his book - this is incremental-ism. This will never produce 0 to 1. In order to produce something like that people should be allowed to innovate - even if initially they have to do stuff like this AtScript or Dart or TypeScript! Criticizing those attempts as "breaking the existing tool-chain" is as foolish as criticizing a spaceship because it does not make use of roads.