I think it would be best if he described what he meant by scalability. I think he meant in terms of team scalability. Since it is the most frameworky it has fewer design decision by your team and devs are more interchangeable. Of course you have to get past the learning curve for that to be true.

It was an interesting read, but I've not had great luck scaling large apps in ng 1.5. State management gets out of control very quickly.

Can it be done? Absolutely! Did it stop me from switching from React + Redux?

Nope!