Yes the answer is simple:
Games are more expensive on steam because Valve is a big mean horrible corporation run by The Man. Games are more expensive on Steam because Big Mean Valve want to charge fat lazy ADHD kids a premium for the luxury of being fat, lazy and having ADHD. Big mean Valve charge you extra because they have gone through the painstaking trouble of removing all your packaging, so while Fat Lazy ADHD kid sits at his computer eating take-away and littering his room with foil tins and plastic packets, he can feel he is donating some money to a good cause, using less plastic than he needs to and feeling less guilty about the fact that, whatever way he looks at it, he is fat, lazy, and has ADHD.
But mainly, Big Mean Valve like to charge higher prices on Steam because every time someone pays that premium, the Big Mean Valve Board of Directors dances a little jig at the Fat lazy ADHD Kid's expense. It makes the Big Mean Valve Board of Director's feel a bit warm inside.
Alternatively, you can all stop looking for someone to be mad at because you cant afford to buy something, and treat it like every other commercial situation that deals with supply and demand.
Seriously if everyone who posted on here about Steam prices -actually cared- about the prices of products, they would be off moaning at Tesco because Sainsbury's sell a cheaper salad, and i believe Asda do cheaper bunches of flowers. Wilkinson Pic'n'Mix is ludicrously cheap compared to that of The Odeon.
Oh right, wait, you just want to point your finger at the big mean computer game company because you cant afford to get your fix. Drugs are expensive, man.