It isn’t confined to BMW or Mercedes although a mate of mine does have numerous instruments and a yacht (plus two vintage cars, a banger, a sports car and a couple of motorbikes) He’s not rich, he’s a retired teacher.

Any half decent car will cost you say between 10K and 20K and in a decade or so will be in a scrapyard. A guitar costing the same price will likely be worth at least as much as it cost originally.