Like Gladwell points out, you have to be extremely well-conditioned to press for a whole game. It takes a lot out of you. So it could be counter-productive if your team isn't in excellent shape, because a poorly executed press (say, if your team is tired) makes it easy for the offense to just blow by you and hit layups.

That said, a team of good ball-handlers can beat a strong press if they stay calm and pass well. Patience and poise.

(Which is probably why the press is so effective in younger leagues: players at that age get frantic under pressure and just don't have the dexterity/skill to keep the ball under control)