This is true for Limit Hold'em, but very much not true for No Limit. Limit Hold'em is a solved game, because as long as you're playing the odds, you can play perfectly. No Limit changes things because the bets can vary wildly. If you play a tight game (just play the odds), and opponent will get out whenever you're in, and will bluff just to see if you call or fold.

Bluffing is a major component in No Limit, and there are very different profitable playing strategies.