The older aikidoka I know (and know of) who are "all busted up" mostly attribute it to overly resistive training. High breakfalls with good landings don't mess you up nearly as badly as refusing to move while people torque on your joints.
I agree completely. High breakfalls can be done very softly, and when done well, they shouldn't cause undue wear and tear. It is when people can't do them very well that these sorts of misconceptions occur.
Case in point: