CellHawk: A powerful phone surveillance tool operates in obscurity across the US

Simple answer might be: no organized coordinated effort was ever made to stop the spread in the US. That surveillance stuff is so much easier in a secret court where you don’t have to answer to annoying “citizens”.

Not enough money in it most likely

Agree with your sentiments, but a phone number isn't a unique identifier we'd care about.

Rather, it is the IMEI (general networking equivalent is a NIC MAC address). Cycling that is what is necessary, but I do not believe that is an easy thing to do - unlike DHCP, there isn't a notion of "connect to cell network, get a cell phone assigned" (for a variety of valid reasons).

A more viable approach is to attempt to severely limit the data leakage from apps and the like, but this is a hard balance to strike between app functionality (example: ride hailing app), and preventing analytics which can be performed based on the data those apps collect and, usually unbeknownst to the user, provide to the telco as part of location services.