It's really easy to do a VR flight sim that simulates what you see out the windshield, but much trickier for the instruments and controls inside the cockpit. Where do you put them? Do you build a real, physical cockpit and AR what's outside? Or do you simulate the instruments in VR space? If so, how? Do you need haptic feedback? To what degree does this emulate real flying?

Not saying it can't be done--it's being done--but it's tricky and not as universally desirable as many non-pilots seem to think.