I believe it's more along the lines of the concepts in IPv4 are easier to grasp than IPv6, starting with the actual addresses themselves.
IPv6 breaks all backwards compatibility. So, it's not unreasonable for people to ask why we can't just break it in a more familiar way?
Extending IPv4 into say, IPv7 and using familiar addressing schemes, well understood routing/NAT/DHCP techniques, etc, while providing the same usable address range as IPv6 is possible.
IPv6 breaks less backwards compatibility than many people think. Many get caught up in all of the other changes you can (and often do) do because it makes life better and conflate that with IPv6 not letting them do things the same way. About the only generally true "it breaks backwards compatibility" is the format of the address being longer for the longer address. Netmask, gateways, DHCP, static assignment, and neighbor discovery are all about as 1:1 as one could ask if that's all you care about but it's just a dumb way to do things if you're upgrading everything so then you have SLAAC, a more present link local, DHCP-PD, and so on to hear/think about as well.
E.g. you can still NAT the massive IPv6 private address space with static and/or DHCP assignments without having to change your understanding (addresses would even be darn short too!) but... it's just silly to do.
What are you exactly asking for? Sure it's not recommended but you can have NAT66 for IPv6, and DHCPv6 for IPv6. You can choose to configure your own IPv6 network in a way that's familiar to IPv4. Not exactly best practice but doable.
IPv6 breaks all backwards compatibility. So, it's not unreasonable for people to ask why we can't just break it in a more familiar way?
Extending IPv4 into say, IPv7 and using familiar addressing schemes, well understood routing/NAT/DHCP techniques, etc, while providing the same usable address range as IPv6 is possible.