Don't think the problem is 64 vs 128. I don't think the problem is end users either, the vast majority of which don't even know what the IP protocol is in the first place (nor should they). The fault I think is on ISPs.

I use hyperoptic in the UK, if you replace the original router (which reserves the external 443 port for itself, i.e. no one sophisticated would keep it), there seems to be no way to get a v6 address. This is pure incompetence and carelessness. Like ISPs allowing their network to send packets spoofing IPs from outside their network. Add to that foreign ISPs (which means that even if your own network supports v6, you need v4 support when you are on holidays/travelling), and you have a situation where v4 cannot simply be switched off.

So for a website, what is the point of supporting v6 if v4 is never going away?