But does AMP makes internet usable on those $40 phones? I have a recent mid-range $200 phone and pretty much the only website the regularly hogs my browser is Google News, which coincidentally is also the only one that uses AMP. It's anecdote, but in my experience AMP (or whatever else Google News does) degrades performance to an amazing extent.
Google News is far from being the only one using AMP and there's a massive difference in loading times and rendering speed for most news sites between AMP and non-AMP versions even on my 1GBit internet connection.
FWIW my impression is not that Google News is bandwidth heavy, but that it is JavaScript heavy. It works fine on the computer but it's hard to use on the phone, even on the same connection.
