Even already, I think you can get away with doing almost everything v6 with a much smaller number of ipv4s for legacy traffic. I say that but still largely use v4 for everything, so maybe I'm not one to talk.
There's a collective action problem around IPv4 vs IPv6. Talking about Azure/Microsoft/GitHub and its lack of IPv6 support is very much an interrelated problem. It's ridiculous to think of noting downsides/trade offs as just kvetching.
