Stats are a terrible and lazy way to tell a story. Rules change. Offensive philosophies change. One can post the same stats and argue different points. You have to watch them play. This is how you have a guy on a 7-9 team win the MVP. It's because someone actually watched the games and didn't just compile data from the box scores.
Also, I didn't generalize. I very specifically named QBs who were not very good.