Steam doesn't set the prices for all those games, that's down to the devs and publishers themselves. This means that SE, and all the other pubs, think that NA, a game that's two and a half years old, is still worth $40, but hey, I see this with all the Japanese games listed on Steam, because Japan, like Nintendo, doesn't like "devaluing" their games (for some greedy reason I'm sure).
Also, as a side note to EGS exclusivity deals, I can assure you that when those games do come to Steam, the devs/pubs will be asking full price. THis will especially be the case for Borderlands 3, and that won't even come with all the DLC trimmings either.
I did point out that the publishers are to blame. "Anyway, it's pretty apparent that for many companies like Square Enix, Capcom, Koei Techmo, Ubisoft, etc., the regular Steam Price of a game is just a B.S. listing made to get you to jump whenever a sale happens."
GoG all the way.
I wouldn't bother with a key reseller site unless I was 100% sure that the dev isn't getting screwed over in some way.