Well steam sales have ran out steam it seems from anecdotal evidence. While the first few were a godsend and a very good piracy "amnesty" - currently I have more than 100 games in my backlog, so on the last two I bought only one-two games. And all around me people say the same. The only games I consistently buy are the humble bundles mostly to support the idea.
Here is some anecdotal evidence that there is is still plenty of pressure in steam sales..
"We sold more copies in the first 24 hours of the sale than we had on Steam in the first three months since release," Fish said, adding that the two-day price drop yielded more sales than the game drew in its first month on Xbox Live Arcade.
All told, Fez sold 105,000 copies in the 48 hours the game was on sale. He also posted a picture of Fez's Steam sales graph to better illustrate his point.