Why corporate profits are at an all time high

(Synopsis and commentary on an Economist article (Buttonwood), July 21, 2012, p.62)
Corporate profits are at unheard of levels.  In the United States Corporate profits amount to 15% of Gross Domestic Product.  The article cites three possible reasons:
The first is a claim often made by business people, that corporate executives are worried about excessive regulation, so are unwilling to make capital investments.  I am not aware of any evidence offered that overall regulatory burdens are any heavier than they were 10 years ago, or 30 years ago.  This argument smacks of setting up a straw man to deflect blame - it is an easy thing to claim and resonates with everyone who ever struggled with a bureaucracy.  
The second is that firms are reluctant to invest because of weak domestic demand, and the euro crisis and slowing growth in the rest of the world is making exporting products less attractive.  (I find this is a plausible explanation for some reluctance to invest).
The third, and, to quote Buttonwood, "the most intriguing", is that pay incentives for Corporate executives are to blame.  As bonuses managers get share options, and the value of the option is usually linked to corporate profits.  Long term investments undermine short term profits, so executives are disinclined toward long term investments as they may undermine their bonus.  In addition professional fund managers may prefer companies who hoard profits as that keeps the companies share prices up, and makes the fund manager's short term performance figures healthier.  So the Fund managers prefer the money go to share buy-bacsk that boost the value of the remaining shares.
Buttonwood finishes by noting "Business-people are among the most vocal in their calls for government deficits to be cut, but if firms spent more, and hired new workers, deficits would fall of their own accord."