[k4ch0w]

I think this is absolutely one of the reasons. Addresses are very hard to remember in ipv6. You usually just have to remember the first 3 parts of ipv4 and then change the last digit based on the host you want. IPv6 I know it has shorthand but still it doesn’t register in my brain the same way.

[Symbiote]

What alternative do you suggest for making the IP addresses longer (so more people can connect computers to the Internet) while keeping them equally memorable?

The most recent anonymous editor to the IPv6 address article on Wikipedia has address "2602:FBF6:0:0:30C6:7069:6DF0:FD24". An IPv4-like notation of that would be "9730.64502.0.0.12486.28777.28144.64804".

[butlerm]

The problem is that adding so many bits to IPv6 addresses, by way of intended integration of the EUI / MAC address in particular is not actually necessary and is a bit of a mistake. As a rule, no one even wants their MAC address propagated across the entire Internet, nor to be registered in DNS either.

There are some technical advantages to doing things that way of course, but they are arguably rather outweighed by the administrative disadvantages. The protocol could have been designed so that typical layer 3 addresses were not much longer, nor harder to type or remember than IPv4 addresses are.