"RB is arguably least important non-special teams position in the NFL now"

Least Important?
and I thought that can't be true for any position that touches the ball 20+ (edited) times a game.
Can we both agree on that?

And based on your comment: "all positions except kickers, tight ends, and safeties average more than running backs" I would conclude that it is due to their severely high attrition rate, not so much the RB position's lack of value to the success of the team.