Yeah I buy them. Now of course there are bad contracts everywhere, but TB contracts seem to be the worst and often result in the least return on large investments.
1) QBs are the most important position on the field. They have a higher bearing on outcomes of games than most other players. Their high salaries/cap hits are largely tied to their importance to the team.
2) QBs can play longer than TBs, typically. The data shows that TBs fall off faster than most other positions in terms of production given the wear and tear on their bodies. In fact, back when Dallas didn't sign Murray, the Cowboys talked about their data and drop off in production at certain "carry" thresholds.
3) As noted, there are many, many, many examples of TBs who see declining production at younger ages than most other positions. Again, it's largely due to the nature of the position, the frequency of hits they take, etc. There are some rare exceptions, such as Peterson, but he was an athletic freak of nature not often seen in the NFL.
It's not even about when they hit a wall. I just don't like putting money in any TB at any time because it's a position where you see teams time and time again succeed and build competent run games while hodge podging it at TB. So I wouldn't even use a high first round pick on a TB. I think the way to do it is churn through mid round and FA TBs and spend your money in the OL, not in the TB.
