The difference is only the end client and server need to support TLS, all the middleware and networks between just see TCP packets and do not have to be privy to what TLS version is being used.
IPv6 on the other hand has to be supported by every middleware box between the client and the server and therefore its functionality is limited by the lowest common denominator.
Additionally TLS upgrades were largely drop in, whereas IPv6 changed too many things at once to be easily adopted.
Hindsight is 20/20, but I firmly believe that IPv6 should have only changed source and destination addresses to be 64 bits and that was the entire RFC.
The difference is only the end client and server need to support TLS, all the middleware and networks between just see TCP packets and do not have to be privy to what TLS version is being used.
IPv6 on the other hand has to be supported by every middleware box between the client and the server and therefore its functionality is limited by the lowest common denominator.
Additionally TLS upgrades were largely drop in, whereas IPv6 changed too many things at once to be easily adopted.
Hindsight is 20/20, but I firmly believe that IPv6 should have only changed source and destination addresses to be 64 bits and that was the entire RFC.