Don't underestimate the threat of rodent infestation...
Until recently a good pal of mine had a very nice late model AMG Merc coupe, one of those V12 jobbies. He parked it up for a few months and then discovered it wouldn't start and all manner of fault codes were displayed on the dash.
He's technically savvy and this sort of thing wouldn't normally phase him but when he investigated he discovered key parts of the loom had been eaten away by mice. As you probably know these big Mercs depreciate at a frightening rate and the cost of replacing such a complex loom made the car uneconomical to repair and it had to be scrapped.
Of course if the car had points, plugs, a carb and a coil...