I don't think its so much that the position isn't valuable to Ted as much as its a skill set where its theoretically easier to find good players with mid round picks and even UDFAs.
Until he got a big draft bargain on Lacy he hadn't brought in a high RB either. I like that comparison because with those two positions are similar in that success is more about vision and fit so they tend to be about as good as they're going to get immediately. This means you can search for an Arian Foster, Alfred Morris, Paul Worrilow, or Vontaze Burfict every year pretty effectively while using 1st round picks to address more difficult needs to fill. With LBs "bum mining" as wist puts it has the benefit of really helping your special teams too.