What does steam have a monopoly on?

It's a little ironic that they reject steam and yet the primary way to get information is the most closed down platform out there, which has more closely (though not technically) monopolized real time chat.

Hard pass from me if I have to join your club to even learn about the game

I found the developers, they have developed other games that are on steam (and their site links directly to the steam listing), weird that they haven't pulled those.