I always come back to the example of WhatsApp and how it took on SMS, IM, and emails and won. People claiming WhatsApp went in mobile first are getting it only partially right. WhatsApp defined itself as a replacement for SMS: No login passwords, no chat history, cross platform and that led to them being cheaper, better, faster, frictionless. Later added MMS-esque capabilities like media and then email-esque features like Groups with super nice execution on the UX front.
Similar thing for AMP pages: It just works and it is blazing fast.