that's not at all true. DHCP was very much part of the operational canon of the internet at the time, which is why it persisted as a model. V6 really wanted to back that out so that networks 'just worked' without depending on an administrator to manage that local service.
NAT was already in use, and a substantial motivation for the IPv6 work was to provide an alternative before it got too entrenched, which sadly failed.
it was first published in 1993. I know it was in common use because I got into into argument with one of the authors, Greg Minshall, in 1995 about how basing it on bootp was really a useless idea. and I used it at my first job which I left in 1992. I sat in on the v6 working group, and remember the discussion about what to do about it. Steve pretty much just drove the consensus as usual and no one had any real objections.
NAT was already in use, and a substantial motivation for the IPv6 work was to provide an alternative before it got too entrenched, which sadly failed.