While it would be ideal to have situations where the situation of a concealed blade or gun is the utmost extreme one and thus life stopping force is rare,  that is not our culture, and our massive borders make it a near impossibility to enact any meaningful gun control.

But beyond that, let's go over the situation where loss of life involving an unarmed or melee only assailant is involved, and assume for the sake of this you are a cop, not seasoned,  but you know how to do your job. Now in this hypothetical let's say you get called to an area because people, maybe black, maybe white,  doesn't really matter, are seen acting dodgy. You arrive and find a guy either looking out of place or doing his best to seem like he belongs, and you figure you might as well start by talking to him.

The conversation starts off like you'd expect, uncomfortable and nervous on both sides,  but it just seems like "don't want no trouble" jitters but then you notice that he's carrying his weight awkwardly like he might have something on him that he's hoping won't be visible as a bulge or worse yet drop down the leg of his pants. It might be your imagination but you feel obligated to check anyways so you ask if he has anything on him,  he gets agitated and less than politely denies having anything and you don't believe him, so you ask to search him. Best case scenario he begrudgingly agrees,  but let's assume the less than best case and he takes a swing at you. Whether or not he connects he's in big trouble, legally speaking, because you don't just assault a cop and get off with a few harsh words. The assailant now has zero expectation of going home that night if he settles down and if he did have something illegal on him he's definitely going to try to avoid being taken in, and while he might not be a killer he is certainly not going to be in any condition to make rational decisions in his attacks.

Now back to you, you were just assaulted, and either you gain the upper hand and pin him immediately or you don't,  and if you don't you still have no idea if he has a concealed bag of drugs or stolen Vintage Voltron collectibles or weapons. You could go for a tazer if you're issued one but that's a one shot only option if I remember correctly and if you miss you're fucked. You could go for the baton but that's gonna do you fuck all if he has a knife or gun. There's always mace but that requires a face shot which is a smaller target. Your gun is the sure fire and safest way to either bring compliance or an end to the situation via center of mass, and unless you're a terminally ill patient with no expectations of living you're gonna choose yourself over him regardless of any training you received. Improved training is one thing,  but it can never override survival in a shit situation where it's your life or theirs.