Yes, there was a study about 10 years ago measuring the longevity of the different positions...RB was shortest career span. I think this is part of the reason that teams moved away from relying on the run and went to the pass (also the NFL changed the rules to favor passing).
One of the interesting things is that the other position on offense that people do not usually want to spend a 1st on is TE and I believe TE was #2 on the injury likelihood list. This because TE's routinely match up against bigger players in the box - not by intention but because they're in proximity to much larger bodies.
I'm all for getting a TE on day 2 who can develop into a starter while the FA signings contribute this year. Tony Gonzalez and Travis Kelce must be outliers as they've had relatively injury free careers.
