> I'm actually surprised that ISPs didn't come together to just build this into their access points.Comcast does something like this (though not technically a mesh) but only for their own customers. If your AP is set to share access, then as a Comcast customer you get a sort of 'roaming' access through any other Comcast AP that is also set to share.
As I recall, it was turned on by default and opt-out, but you were on your own so far as actually finding an AP you could mooch off of. Guest access is always prioritized below the owner.
Also from memory, which may be faulty, out of date, or both: There is some reasonable limit to the total bandwidth you can use as a guest from sharing APs each month (I think it was maybe something like 50GB), and other customers' guest use of your AP doesn't count toward your own data cap.
I also vaguely recall some sort of upsell for your account to remove your data limit as a guest, or at least increase it.
I would guess that if other ISPs start offering their customers the same sort of setup, the next step would be peering agreements between them.