I talked about the
substantial enough to need an installer
line. Like what makes a game substantial enough to need an installer ? Steam and every other game launcher with install capabilities is more or less just a fancy installer. There is no more effort needed for a publisher to generate a new installer binary than it is to generate a new steam patch. Even if gog installers are offline it’s more or less an archive with a binary stub to unpack it and the install script. This one is on the publisher and not on gog. And for the version difference, do you have an example where the gog and steam versions differ ?