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.