After reading your post, I wondered to myself if they actually did get better at QB and decided to research to see for myself. Here's what I found:
Bradford: Games TD/Game Int/Game Yds/Game Completion Pct (career)
49 1.2 .78 225.8 58.6
Foles: Games TD/Game Int/Game Yds/Game Completion Pct (career)
28 1.64 .61 241.2 61.6
In every meaningful category Foles was better, so I'm a little baffled at Kelly's thought process on that trade. I can only guess that Chip thought Bradford had more upside...not sure.
I didn't post this to argue your point, but rather to see for myself if Philly got the better end of the QB trade. My guess is, especially since he gave up a 2nd rounder for a QB that was one year further into his career, that they came out on the short end of that one. Time will tell.
Note: I had this formatted all pretty, but it didn't post that way...I tried to reformat so it was readable but didn't succeed. Sorry for the jumbled mess.