Your mobile data sold, without your knowledge
Many of the apps that sell your location use location as a critical component of the experience. Apple and Google added a permission last year - only allow access to location when app is running (in the foreground). That change has made a dramatic reduction in the amount of location data available.Ultimately, free is the culprit. People like to navigate, buy stuff online, see things on a map, get local weather, and so on - especially if it is free. The old adage about if it is free, you are the product probably applies.