Re: "We have now run out of IPv4 addresses"
64 bits isn't enough. Hardware (EUI-64) addresses are 64 bits, and you need way more than 64 bits of L3 address space to handle 2^64 L2 hosts. The next power of 2 up from 64 is 128, so here we are.
You can already set most of a v6 address to zero (e.g. is 2600:: really so hard to remember?), to the point where anybody can easily make addresses that are ~64 bits of actual stuff plus ~64 bits of zeros. And they go straight into DNS so it's not like you even need to remember them anyway, but if you did then you have the 64 bit addresses you're asking for.