This makes total sense. Sometimes as fans we don't see the dollar impact in light of the cut, only the visceral reaction to the move.
I think we overestimate the market too.
Rosterable running backs are 10 a penny, although Carter is one o fthe better ones available, and also very scheme dependent. And he's not a good blocker so nobody is picking him up for that.
Teams just spent several weeks working with a room to get them scheme ready and won't be super hot to bring a guy in to a new scheme and lose a guy that has it down.
On saying that there are a couple of obvious options for him. Browns only have 2 RBs on the 53 with Chubb on PUP and it's a similar scheme, and the Packers lost AJ Dillon.