Steam services that by injecting more DRM, region-locking games (and accounts) to a set of countries like consoles do, and that is incompatible with GOG’s idea. They can let devs decide on pricing without implementing any rudimentary locks, but then it would be inconvinient for wealthy countries’ gamers to ever purchase a game in their own region unless they intent to support dev/platform. It greatly complicates their side of things and would be a very divisive decision for a smaller storefront that is built around their wholesome image.