Most modern synthetic trainers (and PC flight simulators) have the facility for failing various flight instruments including the ADI and HSI. This ensures valuable practice at limited panel simulation is readily availble to those pilots keen enough to practice. Much depends on the motivation of the pilot, of course. Some are deterred by the difficulty of limited panel practice since it really sorts the men from the boys. But to be proficient you have to keep up regular (weekly) practice on limited panel in a simulator or synthetic trainer.
Saw one businessman who owned a Cirrus practicing ILS after ILS in an Elite model synthetic trainer. He scorned limited panel practice saying it would never happen in his Cirrus. During a holding pattern in the synthetic trainer he was unaware the ADI was "frozen" by the instructor and within 45 seconds he was in ye olde graveyard spiral. He stormed out of the room and took his business to another flying school...