Ask HN: Why Is GitHub Pages Not Supporting IPv6?

Why is GitHub Pages not supporting IPv6?

This is a serious question, no ranting please. I never worked with such a big tech stack nor in such a big company.

Why doesn't a tech company where one could argue it being in a role-model position in the industry put a priority on this? I do understand companies put their priorities where the money is. Given that GH Pages is also a feature for paid customers (for private repos for example), one could argue this is the case here.

Probably one of the reasons is the involved complexity of a CDN. But I'm interested in the detailed reason(s).