I respect your 'totality of contribution' position, in fact, it is my own position.
I think you are not being clear-headed about how detrimental a turnover is to winning games--how the totality becomes negative no matter how adroit the runner is, no matter how much of a nose-for-the-endzone back, no matter how many touches per season.
It's like kicking field goals that subtract points from your total--dumb as a box of rocks. But we accept it...because...? I don't even know.
There are backs who have the trait of elite ball security. They had it in college, it transfers to the pros. It is an attribute like a 40 time.
Kareem Hunt.
Benjarvis GE.
Christian Mac.
Phil Lindsay.
I'll bet there are UDFAs out there who have elite ball security, who lack elite vision or w/e, who can take what their O-line gives them, who do not score own-goals.
Who let you spend more money on DBs and QBs and so on.