If one can afford to spend $5mill on a PC12 to go flying for fun, who cares about depreciation? In the US anyway many of these toys are used to offset taxes so these people buy the biggest they can afford.
IFR flight with TV screens also needs back up steam driven systems to help in the event of failure (of which there seems to be a few).
So what backs up the steam driven gauges in most aeroplane, the ones with a mean time between failure of 800 hrs? The G1000 has a MTBF of > 2000 hrs and also has a set of steam driven gauges as backup.
Present case excluded at the moment, but has there ever been a case of a SE turboprop suffereing engine failure and killing everyone? I seem to remember a Piper turbine failed in the USA, but as they were at FL300 they glided for ages and made a perfectly good landing on an airport.