How exactly would this work? It's my understanding the IP addresses have to be allocated in a somewhat uniform manner to make routing feasible so it looks like

How exactly would this work? It's my understanding the IP addresses have to be allocated in a somewhat uniform manner to make routing feasible so it looks like it would require you to give a block of IPv6 addresses to the customer's router for it to allocate to the attached PCs, phones and what not, which seems like it would take us back to chewing through the address space pretty quick and also not necessarily achieve the desired effect unless the router keeps logs of the assignments it makes. But if every device has a fixed or randomized identifier then surely the identifier contains absolutely no routing information whatsoever (the machine might have an address starting ffff:ffff:... but might be behind routers eeee:eeee:... or dddd:dddd:... in completely different parts of the world).