If Nintendo games had similar price progression of Sony titles I'd agree, but they don't.
Nintendo goes $60 day 1, $50-60 day 100, maybe $40 day 400 (sometimes still $60)
Sony goes $60 day 1, $30-40 day 100, $10-20 day 400
I know if I wait I can get 2-3 Sony games for one Nintendo game. If it wasn't for Nintendo's pedigree of quality I wouldn't even bother. No I see them as a premium system. The PlayStation 3 with all its "$599!" issue was dirt cheap for me for dozens of games costing $5-20 range. Mass Effect 2 and 3 for $10 each, meanwhile Pokemon games are $40 on a DS or 3DS two years after launch when I look. Both are great games, according to taste, but value wise I don't say Nintendo is 2-3x the games I enjoy on Sony systems.