Lots of people do pay private security and alarm firms to keep an eye on things.

It's true that's generally not inside the home, and for most people it's unlikely to be video footage stored off-site.

I'm not sure how I feel about this, we have one nest cam that covers our entrance hallway, and it's off while we're in the house. I like being able to see what's happened while we're away (oh look, the cat came in...) but the privacy aspect is a little worrying. I guess I could get a generic camera and stream to my NAS, using "motion" to detect motion and then back up to the cloud... but that's non-trivial.