There's a couple of drivers for this, both technical and more social (or at least at layers 8+ in the stack).
Part of the reason so many providers get away with one IP address per subscriber is going back to the beginning of dial-up access, where the idea of needing more than a single address per connection was close to unthinkable. IPv6 starts in a world where every end-site is full of networked devices, all needing a v6 address, and comes with an standards document that strongly suggests (not quite mandates) that each end-site (be that an office or a house) should ideally get a /48, but could be a /56 if you want. Even a /64 gets you 64 bits - that's an IPv4 Internet squared! - of host addresses. Allocating a /128 to an end site doesn't even get a mention.
Technically, lots of routers are assuming /64 as the network size, as does a lot of the way DHCP works for v6, especially in terms of prefix-delegation. ISPs are going to have to work quite hard, and give themselves a lot of un-needed support nightmares, to provide end-users with anything longer than a /64.
I had the same concerns as you originally that despite the potentially of the protocol, all the ISPs who want the Internet to work like TV would manage to cripple it, but the more I look at it, the less likely I see this being.