I disagree. The city or state gets sued and they pay the result from the taxpayer funds and literally nobody learns anything, especially not the hard way. Everyone is so completely divorced, and in some cases immune, from consequences that this will change nothing.
The cities and states make laws to better govern police behavior. You can look back on a century of history of this.
After a couple million dollar lawsuits the city or state will learn to be more careful with their methods. It's the taxpayer funds, but it's not an endless supply of money. Cities and states have their own budgets.