That would probably work if there wasn't a ridiculous overabundance of cops in just about all American cities.
As it is, there's enough of them to function as a private security force for billionaires and their property (their primary raison d'être) in greater numbers than usual like this without neglecting any of their usual oppression of minorities, poor people, and especially combinations thereof.
Their numbers are finite, yes. However, those finite numbers are much larger than they need to be and society would be much better and safer for the vast majority of people if there were almost none of them.
Sure, you gotta still use stealth and planning, but you're dealing with a different level of attention.
Vandalism normally isn't a high priority in the cities I've been in. People report it, and the response time is slow, even in wealthy areas or business centers because it's just not an emergency. They'll dispatch a car or two, or the equivalent, but they won't send bigger numbers, and any kind of riot response is going to be slower because they're held back for the obvious target.
Same with small numbers of people making quick strikes at targets that support the main focus of the actions.
Couple that with coordination at targets and false actions to distract, and you can do some decent amount of work in the time you'll have
Chicago has a pretty big police force unfortunately. Looks like around 12- 13k little piggies (source)
So about 25 cops here leaves... roughly 12- 13k cops in the rest of the city :P
ETA: fun facts, the Chicago Police Dept budget is just below $2 billion. That puts it right below Slovakia's entire military budget. Slovakia's population is ~5.5 million vs. Chicago's 2.7 million people.
Chicago alone has almost as many cops as the entirety of Ireland (which has 14.6k cops for 5.3 million Irish citizens)