The argument is not that this theoretical 3rd party would be a for-profit company, but that there's already existing for-profit companies that exist and could s

The argument is not that this theoretical 3rd party would be a for-profit company, but that there's already existing for-profit companies that exist and could serve that purpose, and that the new 3rd party wouldn't see much use because of that. They almost certainly are willing to buy hordes of data off of google/facebook/etc.; it's useful data that they're already negotiating to get. Why, then, would they be want to put in the effort for a warrant on cctv footage when the suspect's google search and maps history they're alreaty getting contain the same info and more? At best, your creating a small amount of competition for data brokers, and I question if it's that much.