I'm not sure "gatekeepr" is the right term when all you do is simply being better for your customers than anyone else. Like, Ubisoft, EA, Epic, they all are garbage companies. GOG is the only store I'd mildly consider (ignoring tiny indie ones like Itch here), but they also have 0 interest in Linux support, which is where they lose me. Without Valve, Linux gaming would not be where it is today, and as a Linux user that is already like 85% of my decision making being done in favor of Valve - with the remaining 15% not all strictly being in another camp either. If someone wants to challenge that monopoly, they'd have to do something better than forcing exclusives or luring with "free" games, because that's some shady shit that makes me just want to stay away even more.