Yeah, it’s weird. Even on brand new gigabit fiber connections in a tech city (Seattle). Quantum fiber doesn’t do native IPv6. WaveG / Astound allegedly supports it but the upstream connection from my LAN would not deal one out. Some packet sniffing seemed to indicate a weird bug.
Compounded by the fact that ISP customer support is worse than useless when it comes to any kind of networking knowledge.
Ultimately, this is the kind of standard that a federal regulation needs to enforce: when an ISP adds or updates a connection, it must support native IPv6. That would have solved this years ago.
My city (admittedly a lot smaller than Seattle) built a municipal fiber network. All new infrastructure. I was astounded to learn it was ipv4 only. And when I contacted support asking when IPv6 would be supported, they ghosted me.