I don't think this is the fault of sales. It's simply a statement that most games' "full" price is more than it would be rational for you to pay given your priorities.
I also own a lot of games on Steam that I've never played, but if not for Steam sales I almost certainly never would have bought most of those games in the first place. The developers may have only gotten 10%-50% from me compared to a full price sale, but if there were no sale they would have gotten nothing. And I still do buy plenty of other games that I want to play more urgently for full price or near to full price.
Also FWIW, I've bought a lot of games over the years and I've never felt "screwed" by a developer because of a price drop after I had bought the game. It isn't like this is a surprising event, it is simply the way of things (and not just for games, but books, movies, cds, virtually all media). It is up to me to decide if having it today is worth $60 compared to waiting 6 months to get it for half that or less.