Firearm deaths per year in your country are only slightly less than auto collision deaths per year. You really think that police abuses of power are a "much bigger" issue than gun control?
De-escalation techniques are part of the standard training for front-line officers here. I would be very surprised if they weren't part of American training.
Since we're talking about Detroit, how about Michigan?
Here are the requirements of the 8-hour pistol safety course for a Michigan CPL:
http://www.michigan.gov/documents/mcoles/CCWSuccCompletion_253744_7.pdf
https://www.michigan.gov/mcoles/0,4607,7-229--148860--,00.html
While the required curriculum includes "avoiding criminal attack and controlling a violent confrontation", it's only one of several topics, and the entire classroom component is only 5 hours. How much do you think is spent on de-escalation or alternatives to lethal force?
Look... the point I'm getting at is this: if you are so quick to mistrust the police, why would you place so much trust in individual firearm owners, who have much less training and oversight?