When it comes to the NFL draft, we pretty much know two things. First, teams will overdraft quarterbacks, picking them far higher than what a more generic prospect rankings list would suggest they should. Second, a lot of these QBs will either bomb or won't be able to make their teams any better.
In the past five years, there have been 17 quarterbacks selected in the top 40 of the draft. Eleven of them have produced at least one season with a 50.0 Total QBR (equivalent to about top-20 in the NFL), which means more than one-third of them did not.