In my dream, SIM cards were kept in a central “Proton SIM hub” of some sort. When someone dialed your number, the hub would reach out to you through an internet‑based app—such as SimpleX voice chat—without ever learning your personal identifying information. You’d answer the call, and the hub would then route the SIM‑based connection to you. Because you were using SimpleX together with a Mullvad VPN, there were no triangular antennas tracking your location. When you wanted to place a call, you’d paste the other party’s number into the Proton SIM chat in the SimpleX app, and the Proton SIM hub would dial that number from its SIM card, establishing a voice chat in SimpleX on your end while connecting a cellular call to the person you’re trying to reach.
Payments to the SIM provider were made in cash, just like Mullvad’s payment method. At present you can’t pay for Proton services with cash, but in the imagined scenario you could acquire a Proton SIM card without supplying any personally identifiable information or tying it to a Proton account.
Would this be feasible in practice?
Your SIM has an IMSI and your device has an IMEI. These are required for your network service to work. You will never not interact with the cell network because of some VPN.
Not if the SIM is in a SIM farm owned by someone else and you’re just interacting with it over the internet, which is the scenario that OP was talking about.
What.
There is a physical SIM or an eSIM (which registers with the device and network) in every cell-connected device.
You can interact with a SIM over the Internet, but you still need to, y’know, connect to the Internet.
If only there was a way to connect to the internet without using a mobile device. Oh well, I guess I’ll just sit and home and dream about it.
If you are connecting to the Internet without a mobile network device then why would you involve a SIM card? Do you understand the point of this post?
Because you want to receive calls and SMS/RCS. Do you?