It takes way more investment to do what you're asking. Collecting the video, getting a warrant, tracking down the person, sending a team to arrest them, etc. How much does that all cost the city? Average cop makes over $50/hr in San Francisco. So it probably costs more than the loss typically?[1]

The problem in SF is that we've disbanded the team that tries to catch people in the act[2]. IIUC, it's both because there weren't enough resources and the DA won't prosecute anyway, so what's the point.

[1] - Maybe not in the case of a-rod: https://www.sfchronicle.com/crime/article/Half-million-in-lo...

[2] - https://www.sfweekly.com/news/authorities-hustle-to-curb-s-f...