FWIW this does not have to be true for companies that do not wish to expose internal nodes. I'm not even talking about the
privacy extensions. I realize that people beat the drums that one must not NAT IPv6 but it can absolutely be a NAT just like IPv4. I would actually expect in most companies that they don't even add IPv6 inside their datacenters, rather they just put a block of IPv6 addresses on some load balancers at the edge and then point their edge devices L4 and L7 mapping to IPv4 nodes in their datacenter. The same could apply to VPN/WAN configurations in some cases much like how mobile networks are configured nowadays. There would need to be some of this regardless due to ACL's required between companies that don't use network VPN's for restricted end-points.
e.g. PCI to PCI environments.In the early days of IPv4 many big companies did not NAT IPv4. I was at a company that did this. Our workstations all had routable public IPv4 addresses. There are still some companies that do this. One of these was a company that had 20 managers and VP's on a call when I just wanted to give their network engineer a CIDR block and a pre-shared secret for a network VPN. I suspect they will be using public IPv4 addresses internally forever. And I doubt they will ever sell their /8's unless people comment on their Vogon poetry.
Amazon is probably one of the exceptions as they have so many geographically disperse configurations it would be harder to continue using RFC1918 address space. Not impossible, just difficult. I can think of a few other big companies that do manufacturing that are spread out around the world that would probably run into walls with RFC1918 at some point. I've seen some of them take over public address space for internal routing which then breaks access to some things on the internet thus requiring double/triple NATs. 1/8 assorted, 25/8 MoD, 26/8 DISA are a few I've seen.