Where do you get that **** from of course steam set the prices it works like this
steam contact x company and say we'd like to sell your game on our site (if it's not a steamworks game) steam will say we want 10,000 keys and the company will set a price for them, maybe a little haggling later steam now have 10,000 keys for a game, then steam will set a re-sale value at a profit to themselves(you don't really think steam is non profit do you)
Even in the sales they don't undermind themselves regarding price. If steam came along and said to x company we can guarantee we will sell 50,000 copies of your game in 3 days you give us the keys for £3.50 each that's £175,000 for the publisher and £75,000 for steam if they sell them at £5.00, now that same publisher would have to sell maybe 10,000 to make the same money but how long will it take 10,000 people to buy it at full price.
Steam is a business not a non profit organization
How does it make them "Non-profit" by doing it a different way?

The publishers set the price, steam take a cut. Similar to the way it's done in stores, except with the games not being physical copies, they don't buy and sell it on, they sell it and take a cut.
Same principles, different method.