While I understand your idea… I’m not sure what you mean with “deprecate”? Who would deprecate stack? Only the maintainers can do that… and even if they do, their users might decide to just fork and keep maintaining it.
There’s no collective decision to be made about it. The only decision a community can do is where to put effort in, maybe what ideas to promote. But that’s about it.
As long as stack has a strong user base and is in a usable state, ghcup will support it (despite the problems it causes for HLS and VSCode).