Time value of money, I 'suppose. It's frugality vs. the "gotta have its;" you can spend $60 over a ton of great games in 3 months or have one now. What that's worth to you is your call, but this is a site called CheapAssGamer. With how quick games lose their retail value, both physical and digital, added with smart shopping on new titles even, you shouldn't be paying full price. Pay to play clubs (XBL, PSN+, BB Gamers Club, etc.) are all eating into game funds that can get more games with patience. I only have Amazon Prime because I use a lot of the features beyond the game discount; I would have it without it a game discount.
There are a few games I have purchased at non-discount prices, but I believe in the past year, it's only been Playerunknown's Battlegrounds and Overwatch, games where having it with the rest of the MP community makes sense. Oh, and I got HZD day one for $31 and BotW for $40. Those were fair trades. Otherwise, it's almost always best to wait.