Whilst I was also a fan of that at some point (and did maintain a cache for my system with v3 builds), but dropped it at some point due to a lot of extra afford needed).
I think without any obvious changes (that I am not aware) it will not happen due to the afford vs cost for the infrastructure etc.
it’s basically the same discussion like here https://discourse.nixos.org/t/pre-rfc-gradual-transition-of-nixos-x86-64-baseline-to-x86-64-v3-with-an-intermediate-step-to-x86-64-v2/