You can find the detailed discussion in the HN link above, but to summarize my viewpoint on this:

1. It already has a much bigger and growing community than any of the new frameworks

2. It has backing/support of Google, when such a big company puts steam behind something than you can be sure it's not going to die out just like that, and will continue to grow and improve, no other framework other than ReactJS has such a portfolio

3. Third-party plugins/components, AngularJS already has some amazing libraries/plugins/directives built that one can easily plug into the project (this is by far greater than any other new frameworks coming out)

and one can go on...