Why Do North American Workers Get So Little Paid Time Off?

Here in Ontario, some of us are experiencing the new statutory holiday today brought to you by the Liberal party, who thought voters could use a day off in the long, dreary days of February.  It was a popular move, except for many employers, who argued the holiday could have devastating effects on the Ontario economy.  This Star story from today is still focusing on this argument against the new holiday.
Well, here’s an interesting study of OECD countries that shows how cheap we are in North America when it comes to time off from work with pay.  Check out this Chart, which shows Canada, Japan, and the U.S. lagging all other countries in terms of mandatory vacation and statutory holidays.  At the top are Austria and Portugal, which require 35 paid days off per year, while at the bottom are Canada and Japan (with 18) and the U.S. with none!  (American law requires no paid holidays, consistent with their philisophy that most employment terms should be left to ‘bargaining’ by employees and employers.  American law also does not require any notice of termination).  I’m not actually sure how the Canadian numbers were calculated–whether it is an average of all jurisdictions or based only on the Federal Code, or something else.   In Ontario, my quick count is 9 stautory holidays, plus 2 weeks’ mandatory paid vacation, for a total of 19–still way off European norm.
Which, of course, raises the question:  Why is it that European employers seem to manage the costs of so many paid days off, while North American employers go nuts whenever the government proposes one new day?  Do you think there is something about our business or social culture that explains the difference?