[dredmorbius]

In the phone market, increasingly, you can go non-contract with pay-as-you-go / prepaid SIMs.

What's starting to emerge is the concept of a WiFi-only device which is usable for voice / messaging when within network range, but not otherwise.

I agree with you generally vis-a-vis power relations -- that's really a highly underappreciated element of economics, though Smith's own second discussion of wealth begins: "Wealth, as Mr Hobbes says, is power".

More generally, organizing politically to prohibit such measures is necessary.

Not merely "making them unlawful to use for discrimination", as there are plenty of other unrestricted grounds for discrimination. But prohibiting outright.