Yep, having sales makes a fair number of people wait until there is a sale. Without sales you're pushed back to a (more) binary decision, do I want the game or not, rather than do I want the game at $X price.
Also with sales you get some portion of people that buy things because they are on sale rather than knowing if they really want the game or not, which can lead to complaints on forums.
Also with sales you get some portion of people that buy things because they are on sale rather than knowing if they really want the game or not, which can lead to complaints on forums.