There were some NAT proposals, but I don't think any made it into the standard.

There is just no reason to use NAT if you have enough addresses. It's a hack to solve address scarcity, and doesn't add any security or any other benefits (unless you don't have a firewall, but you've got much bigger problems in that case!).

The RFCs for IP allocation say that every end site should get a /56 allocation - that is 256 subnets of /64 addresses [1]. A business site should be able to get a /48 (65,536 /64 networks) for no extra cost. Perhaps a mobile device with a cellular modem would get a /64 but that is the smallest allocation.

1. A /64 network has 2^64 addresses.

Sure, but there's not really much reason too (IPv6 still has private/non-routable addresses, so you might want to). NAT on IPv4 is used somewhat like a firewall - because there's nothing to configure - whereas with IPv6 the address space is large enough that there's (almost) no reason to use NAT (that I find convincing), and if a firewall is still desired, that can be run independability (for example, ip6tables).

Edit: To respond to your other comment, no, there's nothing stopping ISPs from inflicting NAT on IPv6 too, other than the consumer asking "why am I behind NAT when there is no shortage of addresses?".

Every device can have it's own address, so you don't really need it as much.

Sure, but if the ISPs number-one goal is putting a stranglehold on your personal freedoms, is there anything actually stopping them from using NAT on IPv6 if they wanted to?

If they are truly draconian cabals of evil, I don't expect "well, you don't need it as much" would stop them.

What's stopping them is their own greed; NAT costs more than not having it.