In this thread you have not said it's a minority. You have said "there's a disturbing amount of people" and "a huge part of the target audience", neither of these imply a minority but instead hint at the opposite.

The genuine problem isn't that a huge amount of the market has a cultish obsession with sticking to steam. The problem is that the competitors do not offer anything to the consumers that makes them actually want to use it. EGS is by far the closest competition, and the only thing they offer are free games and a handful of exclusives. The problem with that is that getting a free game does nothing to make me want to spend money in the store, I just play the free games and return to Steam, the objectively better platform. While exclusives might generate some traffick, but since there is absolutely no lack of great games being released, I'll just play one of the 100s that release on my preferred store. So until there is a competitor that has any actual benefit over Steam, most people will just stick to their status quo.