I think that is true of AP, but not Charles. The only way AP can get 200 carries is if Ingram gets injured or traded. Charles, on the other hand, has pretty weak competition. Last year, Booker averaged 3.5 yards per carry and Anderson averaged 4.0 yards per carry. There were rumblings that Denver's management wasn't satisfied with the play of either running back. Interestingly, they traded Kapri Bibbs who was their most effective running back last year at 4.4 yards per carry.
You make a convincing case for Marshawn. I just have trouble believing that his skills haven't seriously eroded. And while it would be valuable to the Raiders having him grind out 10-12 physical carries for 44 yards each game, that production isn't very valuable to a fantasy team. Especially since he'll get few receptions and might not even get goal line carries since the Raiders drafted Elijah Hood, a short-yardage specialist, in the 7th round.
I won't be drafting Charles, Lynch, or Peterson in many leagues. All three are probably destined to be on the field on a part-time basis. All three are big injury risks or at risk of just not being good anymore. Fantasy championships aren't won by drafting 30-year-old running backs. But it sure would be sweet drafting one of these running backs and having him put up top-5 numbers. I'm willing to buy that lottery ticket in the 8th round if they drop.