the thing that keeps cropping up is this: there are only a very select few white players who have enough talent and self-belief to overcome the racism that haunts them at every level of the game. that being said, as any statistics class will teach you, it takes a large sample to get a reliable result. with white skill-position guys, that's not viable in the current caste system. therefore, any small stumbling block (injury, a fumble, a dropped pass, etc.) causes the incredibly small chance of white success to fall to nil. Abney got hurt in training camp, Suter suffered a knee injury in college, Sheldon didn't have incredible hands, and so forth... on top of the fact that they were white and short, they each had another hurdle to overcome. Welker, on the other hand, was the rare exception, a guy who made a play EVERY time he got the chance. but even that doesn't guarantee success in the caste system, look at Tom Crowder for the Cowboys. he made a ton of plays, stayed healthy, was the ideal size (6'2", 205) and had blazing speed, yet still got relegated to practice squad duty.
it sucks, but for the racist outlook in the NFL to be overcome, a lot of guys are going to have to put up with a lot of crap in order to finally get a shot. and if they ever do, every guy MUST make enough plays to break the pro-black agenda down enough for even the unwilling to notice. that's gonna take a lot of time and a lot of sacrifice from a lot of intelligent and talented white guys who could just as easily do what they've been doing for the last 40 years: moving on to the business world where they are treated with more respect.