Satellite feed time is quite expensive, and the surveillance satellites they have have to be moved into the correct orbit in a lot of cases. You can't just mass surveil the entire planet in fine detail. You can observe a region generally, or you can hyper-focus on specific cars, buildings, people, to the exclusion of other efforts. The demands for imagery is far hire than can be produced, so it really is very expensive to try and get satellite data on silly shit like a single grow house.