crippen
Do the flight simulators have reduced pressure in them?
No, they don't.
The reason, I would guess: great additional cost for little increase in realism.
Most, but not all, simulator work is carried out close to airport level.
If simulating high level cruise or a high level airport at, say, 8000ft, the alteration in aircraft handling characteristics will be reproduced but not the physiological effect of the reduction in pp of O2.