At any rate you choose to buy into Apple ecosystem. A big email provider changing how email works is not the same thing. For the record I host my own email server and use mutt as my main email client. The only Apple device I own is an old pre-iphone iPod.
If Google changes the expectations of email users everywhere then it won't be long until you end up with a broken experience if you don't support AMP email out of the box. Exactly what happened with HTML email: it's not rare these days to receive a multipart/alternative email where the plain text version is simply "see HTML". If AMP mail becomes mainstream it'll be like this but worse. Soon you'll have an HTML page that will tell you to "see AMP content".
I don't know if it's completely on purpose but that's by the book "embrace, extend and extinguish" by Google there.