If UBI's DRM scheme is unacceptable...

[Avimimus]

Btw. It is worth noting that the first generations of flight sims were produced with less DRM and markets that were many times smaller. In fact, flight sims were much more popular when the markets were tiny in the 1990s.

Of course, the amount of labour required and overall fidelity was also lower (smaller budgets) - but we shouldn't pretend that the genre won't exist without invasive DRM.