Matt Leinart won a National Championship in college. Threw for over 300 yards vs a Texas team that had 5 DBs that went on to start in the NFL and was considered by many knowledgeable NFL people to be the most NFL ready QB in the draft. Palmer has never had a season this bad in his 10 year career. Kolb was Offensive player of the week in Philly.
So no, they all weren't crap to begin with. They only got that way when they showed up in Arizona.
Matt did nothing after he left the cards and failed to impress many scouts to pick him up or give him a starting job on most teams. The Cards didn't DO THAT to him. Also, there have been many good college QB's that didn't translate to the NFL. NFL teams don't do that to those guys either.
Palmer is EXACTLY what he has always been with the Cards. He has thrown double digit interception 9 out of 11 seasons. Two of those seasons he could of reached 20 and two of them he did. His pattern in his last two stops was the same. Throwing up ducks, untimely interceptions or missing wide open guys. He just has had some good streaks. Again, the Cards didn't do that to him.
We got a guy who has been overrated, inconsistent and at the end of his career. The Cards didn't do that.
I think the ownership has mishandled tons of players since they came to Arizona but these are not legit examples of it being the Cards fault.