Says who?
If you're an indy game developer, it turns out that just posting .exes on your website gets you a limited reach.
On a more fundamental level, it seems like people will pick convenience over security and freedom every time the choice pops up. In the land of media, this comes down to choosing to put all your eggs in one basket in exchange for having less control over the products you bought. We've seen this across Netflix, Steam, and Spotify as the largest modern examples.
I don't get to declare it one way just because I think it's true either.
If people truly want all their eggs in one basket, is it market capture if you are 100% upfront (which these companies aren't, but lets suppose), and people come into it anyway? I suppose my philosophy here comes down to "you can only protect people from themselves for so long before exploitation simply becomes business". Why try and spout freedom to those who actively seek someone or something to be controlled by? Why spout principles of ownership to those who will relinquish it every time for a "cheap" subscription?
Now the real answer is another scary word to this community: regulation. It's been beyond time we had proper digital ownership laws. But we're a very long road away from that in the US.
By random googling I found that they have 200 million active users, who bought 16 billion in gross merchandising value?
18 thousands of games launched there per yer?
Arguably if someone is in PC gaming, they at least know what Steam is?
Would you say the market demanded Ticketmaster based on the results?
However Ticketmaster is a monopoly. There are (still) alternatives to Steam.
But yes, it is getting into a monopoly, or oligopoly position.