Earlier quoted context omitted.
What is even better now phone calls are prohibited, but all these airlines had actual credit card phones installed in every seat just 20-15 years ago and really wanted you to do phone calls for $1 a minute. And some people did, and it was annoying, and it was “fine”. Now that they can’t charge extra suddenly it’s “against regulations”.
Can you potentially see the difference (red-tape-wise) between a centralized/trunking FAA-certified radio on one highly-specific frequency vs. random, uncertified rogue transmitters all over the spectrum? This wasn't a carrier regulation.
Calling over the cellular network has been prohibited since time immemorial. What the parent comment is talking about is carriers also prohibiting making calls over airplane-supplied WiFi.
You can't, for example, join a Zoom meeting, or use your phone's built-in WiFi calling ability, on a typical flight nowadays, for better or for worse.