From where do you get this number? There’s certainly many servers that provide services both via IPv6 and IPv4. But just as there are many servers that provide services over IPv4 only, there is already a significant, and ever-growing number of IPv6-only servers. Be it because those are often cheaper to obtain nowadays than servers with IPv4, be it that the IPv4 side of things is too challenging in some zones so dual-stack servers are enabled for IPv6 only, or for other reasons (e.g., shared IPv4 address only but dedicated IPv6 address(es)). There’s even zones that provide services only via IPv6, just as there are zones that only provide services via IPv4.
What is certainly true is that overall, IPv4 traffic certainly is in the majority. But while most underserved zones suffer primarily from too much IPv4 traffic, there are a few with high IPv6 adoption rates where also the IPv6 side of things can be quite challenging, e.g., India, Pakistan, Bangladesh, to name a few, or some in South America. So a differentiating approch is needed.
I don’t really understand yet what you mean by that, but it certainly needs to be given some thought as to how to account for the mix of IPv6 and IPv4 traffic, and that the load on some/many servers comes from the combination of both.
I think as a starting point, it could make sense to consider the two independently, and see as one digs through the data as to whether a clearer picture emerges as to how best to combine the two into a single picture. Also considering that the “net speed” setting is separate for the two protocols for servers that support both, so a server operator can tweak them to their need to get an overall traffic volume/rate that matches their capacity.