This is not a team who is Super Bowl ready and needs to have experienced guys "just in case" at every critical position.
Besides, in today's game 30 and over is positively ancient for a RB.
The Rams are in "do-over" mode (as opposed to rebuilding). The "do-over" mode means they have a core of good young players that need to be developed and molded into a playoff team, no doubt with some better pieces added at some positions.
The last thing the Rams need is a vet well beyond his prime in the backfield. They need up and comers; not over the hill-ers.