That would have been true if parcelling out a /64 was actually easy or common. In practice, it's designed that one /64 is one device, and it's really hard to sp

That would have been true if parcelling out a /64 was actually easy or common. In practice, it's designed that one /64 is one device, and it's really hard to split up that subnet, with SLAAC outright making it impossible. It's possible with some static configuration, but that's not something an average Joe is going to use, and router software I came across usually considers it an unsupported option. EDIT: disregard that, the /64 is actually the smallest subnet. It does hinder subnetting fun, but not allocation to devices. I'll leave the invalid post for the sake of transparency.