Seriously? Does local law enforcement maintain marksmanship proficiency?

It may seem excessive, but let's keep a couple of things in mind:

1) combat shooting is not the same as target shooting. In combat shooting not only is your adrenaline pumping like crazy, but you may be winded from running, shaky from fear or not getting into a good firing stance because or getting a good sight picture because the other guy is trying to kill you! So yeah, it's VERY easy to miss under these circumstances.....even by experienced and skilled marksmen.

2) even if you get solid center-of-mass hits, real life is not like the movies. In real life, pistols (and guns in general) are not death rays, where the target is blown back 20ft and dies instantly from a single hit. In real life, assailants can absorb multiple hits before they go down, if they go down at all. And unless you hit the CNS (brain or brainstem), they are not going to be incapacitated instantly. In most cases incapacitation comes from exsanguination...but that takes time. Even a hit to the heart will still allow the assailant about 5-10 seconds of consciousness before they lose enough blood to no longer be able to perfuse the brain.

3) Cops are taught to shoot until th threat stops. Factoring in the above two caveats, it is entirely possible for a cop to expend a full magazine of 9mm (which with 17 rounds sounds like they are using Glock 17s) before the assailant is no longer a threat.

So hear is my take. 9mm is a bullshit round and with 17 rounds that what it was (Either SW M+P or Glock). You can show me all the data and tell me it is all about shot placement and how good ammo is now. The truth is the bigger the hole the more blood pours out. You may have to shoot somebody multiple times with a 9mm to get the threat to stop. If the threat is still real, keep shooting. A well trained person can shoot accurately as fast as 5 rounds a second so that is 3.5 seconds of firing. Not a lot of time when a guy is shooting at you.

The public thinks, that you shoot a guy a couple times and he falls over dead, just like in TV. That is not how it works. These guys were both firing so there is an adrenalin dump, your using a wimpy round, I am sure both of them are shooting on the move so there are some misses for sure, and your pulling the trigger till the treat stops (at 5 shots a second). 17 rounds is not that much. Now are they going to cry in St Louis about the poor kid that was trying to kill a police officer. You bet your ass they are, because...hell, I don't know why they are crying...You shoot at the police and you get killed...sounds right to me.

Not having a video to see the chase and assess the scenario it's hard to second guess anyone. Being shot at from rather close distance is enough to put anyone's adrenaline in hyperdrive, which only makes the shooter's control more erratic. Then we add a possibly erratically moving target and a probably erratically moving shooter and I can see lots of possibilities where misses would be the norm. It's definitely not like the range at all. Most of us, military or cop, never achieve the sniper standard of "one shot, one kill" or even approach that mantra.