Angular team member here. These are our observations as well. Based on metrics we collect (opt in telemetry, website traffic, language service downloads, etc), there are over 1.7m developers using Angular.
I'd say that many of them are in the enterprise, but there are also a lot of startups that bet on Angular. This is mostly due to the integrated stack where folks need to make fewer decisions and get smooth updates across versions.
Stability is another factor. We validate every commit pushed to the Angular repo with 2600+ projects inside of Google. If any of their tests break we rollout automated migrations or rethink the implementation.