In my other life (aviation) airplanes that have sat for years with little use generally are not a good deal. A high-time machine that has been flown regularly and maintained well is generally a better bet than a low-time hangar queen. Do you suppose the same thing could be said about Jeeps?
Yes, this is true about anything with an I.C.E.
There was a story years back about a guy who bought an 2001 E39 M5 (BMW) with 5k original miles. He paid a shit ton of money, and shortly after buying it (once he started driving it) he began having countless numbers of engine problems. Oil leaks, coolant leaks, etc.
He had to end up taking the engine out and replacing every major seal, gasket, etc., which on a BMW costs a small fortune.
The moral of the story is that if you let a vehicle sit and those gaskets don't get lubrication, they actually start to rot and go bad.
60k miles on an vehicle like this is one thing, but 15k miles is actually something I would be concerned about. From a collectors stand point, it makes sense, but if you intend on driving it, buy one with more miles on it, unless you want to start replacing everything.
When it comes to engines, sitting is actually worse than driving IMHO.