I think this approach gets the whole industry to adopt it.
Consider the opposite approach. If they let airlines charge any amount for it, the airlines that installed it would make it expensive. No one would use it. Other airlines would feel no pressure to offer it.
By making it free, it gets used, and eventually depended upon. SpaceX are making free wifi the expectation from consumers on flights.
Correct, I’ve had Starlink in several long haul flights over the past 6 months and it’s already becoming an expectation, ie makes the flights without it noticeably worse. I’m not sure whether everyone gets it for free, though, it was my understanding that it’s complementary for business class but a paid add on for economy. But once you have it, it’s fast and stable.