Climateer Line of the Day: Jeremy Grantham on Profit Margins Edition

MarketBeat had two posts on profit margins yesterday (links below) and I, thinking that we had posted the last word* on the topic [tell them about your modesty -ed] figured that subject had been beaten to death.
Not yet!
Here's Vitaly Katsenelson's ContrarianEdge bringing home the money quote in "Margin Shrinkage – It Can Happen to You":

“Profit margins are probably the most mean-reverting series in finance, and if profit margins do not mean-revert, then something has gone badly wrong with capitalism. If high profits do not attract competition, there is something wrong with the system and it is not functioning properly.” – Jeremy Grantham

Well there you go.
Here are the two MarketBeat pieces:
The Great Debate on Margins: Can They Keep Going Higher?
which was followed by
The Great Margins Debate: Another Analyst Says Don’t Worry

*Dec. 29, 2010
 "S&P: CORPORATE PROFIT MARGINS TO BE SQUEEZED IN 2011"

Nov. 30, 2010
"Corporate Profits: What the Current Level Tells Us About S&P 500 Returns Over the Next Five Years"

Nov. 11, 2010 
President Obama Has Been Very Good For Corporate America