No one expects Steam to put their own titles in a rival store. You don’t buy Halo on Mac
It would be a good thing if Half-Life Alyx came out on other PC game stores, in exactly the same way that it would be a good thing if a game like Control came out on other PC game stores. Our expectations are socially constructed and we should question them more.
With so many different stores to download apps, it gets increasingly unlikely anyone is going to take the time to cross list on all of them.
If we wanted to change how this worked, I feel like we’d need to consolidate on fewer marketplaces. For example, apt-get has access to a huge variety of packages so I don’t find myself using the Ubuntu App Store or random third party marketplaces as much as I do with games.