Actually, Achievements are a massive selling point. Many games have been sold thanks to that little addition. Believe me, Sony would have sold more games when there was 'nothing' on the PS3.
It's a business mistake in the terms that it was free to implement and would have reaped financial reward over the lifespan of the PS3.
There was news before pertaining a link between achievements and the selling of games and that they had a positive effect on games sold.