It’s not. By time a pilot gets to this level of aircraft, they have 1,000’s of hours or literal years of instrument time and actual IFR. Thats time spent actually in the clouds and not simulating. Jet aircraft and many turbo props these days are pretty much almost completely flown on instruments, say 99-1%. So at this point in our careers, most of us can fly instruments better than most other things. We don't fall prey to spacial disorientation, we trained for it and have done it so much we can do it completely exhausted.
