I don't really even think the comparison to a player like Iverson in hoops is valid. Basketball players slow down over the course of many years. KG's not the player he was four years ago, but he's still very effective. If he'd accept the role, AI would be a top reserve on any team in the league, even though he's not good enough to start. Guys like Ray Allen, you can see they aren't quite the superduperstar they once were but they remain very effective over time.
Football players, it's much more hit-or-miss, at least for skill players. Guys don't just start not being QUITE as good, they go from "All-Pro" to "Major Suckitude" within the course of a season. How fast did Marvin Harrison fall off the cliff?
LJ's done. He's not good enough to help a contending team, and no rebuilding squad wants to take him on because they're... well, rebuilding.
Why aren't people clamoring to go pick up Edge James? Edge rushed for 1200+ yards in '07 - '08. Larry Johnson hasn't been relevant since the year before that. Edge is only about nine months older.
Why is one player completely forgotten, and the other gets people's panties all moist? Old running backs don't gently fade away, they take one too many hits and they suck. His crappy attitude is irrelevant, LJ is done.