The optimal level of crime in cities is not zero.
If you don't have drunk people doing stupid things or the occasional drug dealer slinging contraband, you probably live somewhere very boring. If you don't have teenagers breaking stuff and tagging walls, you probably priced out all the families.
If you don't have ethnic mafias harassing each other, your city probably doesn't attract a healthy diversity of immigrants. If you don't have ethnic mafias at all, you've probably atomized everybody in dangerous ways.
Most importantly, if you have no visible crime whatsoever, you probably live in an authoritarian police state with very little cultural dynamism and a criminal class directly integrated with the security services.
You cannot restrict human behavior to inflexible social norms all the time, and trying to do so is exactly the kind of high-modernist imposition that did enormous damage to so many people who lived through the 20th century. Life is messy, cities should be messy too.