It's not a case of a lack of flying skills or confidence, it's a basic human limitation
Sorry, Dan. Must differ with you on that subject. It is a basic airmanship manoeuvre that should be taught on all aeroplanes. An all engines manually flown go-around from the flare and on instruments, should be taught as an essential part of a type rating in any aircraft; whether piston singles, turbo props, or jets. There can be no excuse for avoiding this in a simulator. Put bluntly, if the pilot under type rating training or being tested for instrument proficiency in the simulator, cannot fly this manoeuvre on instruments competently during the type rating training, then the instructor has no business in signing him out as competent. But commercial pressures on the instructor to keep within cost/time schedules often mean short cutting takes place on the quiet and the candidate is signed off when he shouldn't be.
Unfortunately, the accent during type rating training in the simulator is invariably biased from the first lesson towards full use of all automatic features. These include automatic pilot go-around manoeuvres where the press of the TOGA feature neatly disguises by default any shortcomings in the pilot's basic instrument flying ability. No problem if the main purpose is to tick the box and quickly move on to something else in the syllabus.
Spatial disorientation may well be (as you rightly say) a basic human limitation. Notwithstanding, it is also a convenient excuse often used for lack of flying ability on instruments. Even in accident reports where the investigators have a pretty good idea that a pilot stuffed up a low altitude go-around, then it is all to easy to slip in spatial disorientation as a contributing factor that explains everything; even though it can rarely be proven.