If you mean, why police would ever be involved, the answer is that there are a lot of police and not a lot of municipal workers walking around. The only way municipal workers would do anything here is if a resident of the area contacts them with 311 to inform them. And even then it can take months (if ever) if it's something like a blocked sidewalk or broken bollards rather than something important like a pothole.

If you mean why would "authorities" care, there's a lot of people that put what amounts to trash on the sidewalk and then move to a new apartment without cleaning it up, or else just ignore that they left it in front of their house until "someone else" takes care of it.