It wouldn't be terrible if they charged per unit of data transferred _at a sane level_, we're just all aware that if they switched to this model (which exists in some places like South Africa) then they'd gouge us over prices... it'd also introduce an interesting social dynamic since sites that push megs of ads on you would literally be taking money from your pocket, instead of just wasting your time.

It'd actually be kind of neat if bloatware were discouraged this way, since currently there is no cost to bloatware as long as whatever it is remains within the acceptably performant range.

Doesn't Google Fi do exactly this? They charge $10/GB for data.

$10/GB is high. Purposely high, because the point of Google Fi is to use WiFi as much as possible and avoid cellular. So it's there if you need it but you don't want to need it much.

This hardly works for the connection which is actually providing your WiFi, or if you want to try to use cellular exclusively.