This isn't really news, as it was apparent, or at least should've been apparent, to all with the slightest understanding. Facebook does the same. Sometimes these are called 'shadow profiles'.
Here a paper mentioning it: https://www.scss.tcd.ie/doug.leith/apple_google.pdf
Mobile Handset Privacy: Measuring The Data iOS and Android Send to Apple And Google
We find that even when minimally configured
and the handset is idle both iOS and Google Android share
data with Apple/Google on average every 4.5 mins. The phone
IMEI, hardware serial number, SIM serial number and IMSI,
handset phone number etc are shared with Apple and Google.
Both iOS and Google Android transmit telemetry, despite the
user explicitly opting out of this. When a SIM is inserted both
iOS and Google Android send details to Apple/Google. iOS sends
the MAC addresses of nearby devices, e.g. other handsets and
the home gateway, to Apple together with their GPS location.
Users have no opt out from this and currently there are few, if
any, realistic options for preventing this data sharing.
As usual, academia is late, but it's nice to see some acknowledgement.
Keep your devices offline outside. If there is an emergency, you can always turn them on again. Not that the internet would be useful in an emergency. Before you finished clicking the GDPR nonsense, the cookie banners, or 'voluntarily' accepted the TOS, an actual human being will have helped ten times.
This is just a tiny piece of the puzzle, and Apple is not the biggest player in the field. Google has incredibly large datasets. Even the tiniest bit of information can be and is used against you. Scale makes it trivial to correlate anything they want.
Any corporation 'advanced' enough engages in such practices. Guess where the data for 'fast' location search comes from? Google knows every Wi-Fi AP out there. And has the money to store every piece of extractable data. What seems harmless at first has far-reaching consequences and hurts every creature on the planet.
We must not allow normalization of digital abuse. Don't be lazy and complacent.
The hipster 'my body my choice' crowd will continue boasting with their expensive iPhonies nonetheless, depriving you of your 'choice', I'm sure.
Some are more equal than others.
