How come we don't know why the oil-rig blow-out preventer failed?

A few months ago the API (American Petroleum Institute) started up their
TV commercials that they run during the 6:30 national network news
broadcasts.

These are the commercials that has some soccer-mom milf prasing the
wealth of oil in "america" and extolling the virtues of opening up alask
and the gulf to more drilling.

TV Commercials like this one:

http://www.youtube.com/watch?v=fdNUWVs6fmI

woops - sorry. I mean like these:

http://www.youtube.com/watch?v=C57m2va1FXw
http://www.youtube.com/watch?v=32VgYHuj_mk

These commercials were running pretty steady for the past few years but
mysteriously vannished from the airwaves after that oil rig in the gulf
decided to behave badly and blow itself up (I wonder why we don't know
the results of the investigation into why the blow-out preventer
failed...)

If you notice the second commercial - the chick mentions oil and natural
gas "from America". That commercial was uploaded 2 years ago.

A slightly different version of that same commercial is airing currently
during the evening network news broadcasts. In this version, oil-chick
says something like "bet you didn't know that 2/3 of the oil and natural
gas we use comes from right here in "NORTH AMERICA".

Finally, we Canadians are getting some recognition that if it wasn't for
us, you americans would all be wearing burkas and white dressing gowns
and living under sheria law because you'd be owned by Saudia Arabia.