We're talking about Valve. Valve makes a game = people want to play it. Causality works both ways.
When that happens it's because you have the potential to either make a better game (hard), sell it at a lower price (kinda hard) or invest less while still expecting some copies to sell (easier).
Valve makes games that are almost untoppable and sells them for free, and then constantly adds content that they offer for free as well.
haha! yeah! Everyone will suddenly make perfect games and then they will all sell millions.
here's what I'm saying.
Valve makes the best games.
They have an incredibly loyal fanbase.
Not only do they have the ability to release those games and additional content for free, but doing so is actually arguably more profitable to them.
It's all good for customers who just want Valve games, but for the rest of the industry, Valve is a force that can't be rivalled with and if they decide to release something in the field where you were previously having some 'normal' competition with other publishers, on PC, Valve can simply crush you all into dust. Competition is healthy, but this isn't competition, it's murder.
Now add to this the fact that most of the money they make, they make by taking a precentage off your profit on Steam, which is so ingrained into PC gaming culture that not releasing games on it not only costs you like 98% of the userbase, but will also trigger fanboyish 'pirate boycott' behaviors.
See what I mean?