I am well aware that a cell phone position data belongs to the cell service provider. Most people are not aware that cell phones are in regular communication with cell towers over a “Control Channel”. This is how the cell network knows which cell tower to route to when there is a call to your phone. As you move with your phone, the phone gets handed to new cell towers when needed. Your cell phone information communicated to the cell tower on the control channel included the GPS location of the phone. Many people think that the cell system only knows your location when you make a phone call, but that is not true. The cell system is receiving your GPS location on the Control Channel often enough that it can be considered to be constantly tracking the location. And you are right that the location history is available for purchase by advertisers or by the government.
And with 5G it tracks in 3D and within decimeters, even without the GPS component.