Eh? CGNAT is purely a cost saving measure. I have no idea who would try and run a pure IPv6 network for (i assume given Roku etc) home use and then get mad that

Eh? CGNAT is purely a cost saving measure. I have no idea who would try and run a pure IPv6 network for (i assume given Roku etc) home use and then get mad that some stuff doesn't support IPv4. The 71% is almost certainly because Roku consumes a lot more bandwidth doing video streaming than the other services. Even if Roku did support it I'm sure the users wouldn't be happy that xx% of the web was unreachable.