Why do the majority of American cars suck?

I just read consumer reports, forbes and msn autos. At least 2/3rds of every worst rated list is made up of American cars. Why is this? I've really wanted to believe American cars are good but my own experience has really dampened that feeling so don't say I don't know what I'm talking about. I know there are exceptions(the Ford Fusion, Chevy Impala, mustang) but out of the 20 American cars I've owned/driven including the above the rest have SUCKED(pt cruiser 2007 WORST CAR EVER). So please tell me what the real facts are and what your humble opinion is on US cars/brands.