Contact tracing apps didn't get installed enough to be effective. Turns out they weren't needed. Tracking without warrants is already possible when there is a will.

Unless people stopped dragging their phones around, the information is already there.

Dumb question here, but why isn't this being used for the thing, contact tracing, that everyone claims is what we need to stop the spread?

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

Cellhawks existence should not unfortunately come as a surprise to anyone watching the privacy space. I hope to see privacy respecting vendors selling phone numbers that can be quickly cycled one day.

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.