>I think this is the kind of thing that happens when only one company is behind a product.
Probably true but not the whole story. The problem with every js framework is js. Goog is going to yank the plug on js. Its not going to happen tomorrow but hopefully sooner rather than later. Its going to rally the troops and we are going to see a stampede to whatever their next product is. Double edged sword IMHO. JS is awful but whatever Goog comes up with will most like not be much better. Or maybe it will be better. I don't know.
This is the same spot MS was in five/seven years ago.
They's been pushing an alternative for awhile.
AngularDart is actually a very different design, it's not just a Dart port of AngularJS. It really takes advantage of Dart's featureset. The Dart language itself should seem much more familiar to Java/C# programmers. It's a very clean/well designed language. Strangely though, it hasn't caught on compared to JS. JS still remains the gold standard, despite all the alternatives (I've been a fan of CoffeeScript for awhile).