> every publisher with more than one game has their own launcher (usually shitty and brings no value)

I view this as a positive -- it's not feasible to maintain a build for every game and storefront's DRM/auth (unless you go DRM-free, which is the ideal but not something publishers and developers do on release). A launcher is the layer that sits between -- the games are written to auth against a launcher, and the launcher has builds for each storefront.

Otherwise you're just further entrenching Steam as the de facto monopoly on sales.