Originally Posted by
ponderingturtle
It isn't simply one thing or one reason.
This.
Also, as I pointed out, requiring Congress to change its rules against their will would require a constitutional amendment. The unintended consequences of such an amendment are unpredictable. Not only would it not solve "the problem" (as if there were one single easily identified problem), it might cause any number of new ones.
If you don't like obstructionism, vote your members of Congress out of office.
I suspect that many in the Tea Party Caucus think that blocking some votes is what their constituency wants them to do.