In this specific example there is a very big difference between producing a format for use in a first-party app vs trying to replace standards for content used across the web.
I mean... sure it could have? There could have been an independent "AMP Foundation" that forked the standard away from Google and owned the evolution of it from then on. Like how SPDY was forked away from Google ownership into HTTP2.
They kept opening it more and more but by then it was too late.