Except that one could persuasively argue that non-lethal force then VALIDATES and encourages easy escalation of force to those levels which is (likely) often unwarranted.
"I'm just going to taze him, it's not like it's going to kill him"
I truly wonder what would happen on the large scale if we took non-lethal force away from cops.
My guess is a large swath of shootings as criminals 'tested' to see what they could get away with, or didn't believe that things were now lethally dangerous again, but eventually I suspect cops would get fewer challenges.
And lest we forget, as "broken" as people perceive the US system to be, violent crimes have been steadily decreasing to their lowest levels in 30-40 years.
Exclude urban minorities, and the crime/violence rate in the rest of the US compares very reasonably with the rest of the developed world.