I disagree. I believe they do go get another RB because most NFL teams no longer feel comfortable with 1 good back. But I think Jacobs has shown in his few opportunities that he can be more like a Christian Okoye type back than a Ron Dayne bust.
Problem is in a dynasty league, big guys don't often last many years because of the pounding. Bettis was a rare treat at that position for his size. Jacobs could very well be the 1st and 2nd down back with a smaller 3rd down back next year.