Buffalo was 6th in rushing yards.
Look, you don't have to rush for 200 yards per game, but you do need a run game that keeps you on schedule and doesn't have you constantly in long down and distance. That's been the Texans main issue the last few years. They are always in 2nd & 9, 3rd & 11, because they have so many minimal to negative gain plays in the run game. Hard to be a consistent offense like that.
Now, I agree that you don't need to spend a ton of resources on it, particularly at RB. The o-line and the scheme are the most important things. Now you do need a RB that has the talent (vision, quickness, patience, etc.) but you can find those just about anywhere. Philip Lindsay sucked here, but he was a UDFA in Denver who started with two 1,000 yard seasons. Arian Foster UDFA. Terrell Davis a 6th rounder.