So it's not really about speed. As with anything that eschews standards for its own modified version thereof, it's about lock-in. Tons of pages in Google AMP markup mean tons of pages that are optimized specifically for Google and indexed primarily by Google and shown primarily to Google users. It's Google's attempt to match Facebook's platform. And yes, Facebook is far worse than AMP, but that doesn't make Google AMP a good idea. At least Facebook doesn't try to pretend like it's open.