I was genuinely asking what you meant by "always" when the police have been around 180 years and the ability for individual homeowners to be recording footage of whatever they want in common usage has been around maybe 10 years.

Given that link, I would be very surprised if the Minnesota Police heard of Leo Theremin connecting a camera to a TV in the Kremlin in 1927 and immediately organised a map of citizens with cameras they could "ask if they have footage and are willing to share it"; the link says CCTV was a military thing until 1950, was expensive and uncommon until the 1960s because it needed someone always watching the feed, so ther ewouldn't have been any recordings for the police to view for over 40 years. Then "it wasn’t until the late 1990s that it started appearing in mainstream camera products like security cameras for the average business or home."

I'm guessing the time the police would routinely ask if anyone had footage of the crimes would be sometime after that, after CCTV recordings became popular enough in businesses that there was a good chance of a camera seeing a crime in enough cases to make it worth organising. Maybe mid to late 1990s for businesses? Then, individuals with things like Nest Doorbells ("homeowner surveillance camera program") wouldn't be a thing until maybe 2010s?

Which makes me think it's an odd thing to say the police "always did this".