I think it's perfect as they are and I'd advise against changing it.
I personally discourage the use of stack or ghcup, and would certainly prefer to see more installation methods based on package-management tools that each OS provides. I think there's something to be said in favor of using standard package-management tools that install the compiler in global space.
In particular, the PPA-based installation method for Debian/Ubuntu/Mint
that HVR used to maintain was excellent. It's still my preferred
method (even though it's not maintained). I don't know where you are getting info about which project is used more or less, and I fear there may be a strong bias.
Leaving them there is more fair, makes more people aware of their existence, and makes
it more likely that newcomers will be able to participate in other efforts.
For Haskell to remain a community project, it's good that we keep mentioning less popular projects, even when attention temporarily sways one way or another. If you remove other projects from the web page, you create an effect of
compound interest (or compound attention) towards those projects, where
they get the most contributions because they are the ones that most
people are aware of because they are on the front page because they get
the most contributions, and so on and so forth.
Ivan