It is and there where actually not, it will, soon.
FYI:
And I dare to predict that even in professional flight simulators, the far better than flat but nevertheless imperfect dome projection will soon be replaced by VR/AR.
With AR training, already in use by military, you can combine the irreplaceable benefits of 360 degree view and depth perception with the ability to operate „real“ instrumentation.
VR rulez and I can only recommend anyone to give it at least a try.