Valve "played capitalism so well they broke it" and now Steam can't be replaced
(www.gamesradar.com)
You've avoided doing this built all your arguments on the very thing you refuse to provide, so I'll do it.
exclusive ownership through legal privilege, command of supply, or concerted action specifically : exclusive control of a particular market that is marked by the power to control prices and exclude competition
The most popular and best does not mean only or exclusive. They made a better product, that's it.