Nice work Phinsfan and thanks for the interesting post.
Now go to work on this. How many of the QBs you mention were starters in their 1st, 2nd, 3rd years? How many were benched to come back either with their original team or another team and succeed?
Being in Denver I look at Orton. He was a starter, backup, starter, backup at least 3 times for Chicago. He is now in his 6th season and has been very successful for the last two seasons.
Would be interesting to find what the average really is.
Oh, and yes you have way to much time on your hands, but I'm glad for it.