Most people could probably tell apart wine by style (somewhat), not by price, which is if not arbitrary then a result of factors that don't necessarily reflect

Most people could probably tell apart wine by style (somewhat), not by price, which is if not arbitrary then a result of factors that don't necessarily reflect "better taste", and non-avid consumers wouldn't agree on what "better taste" means anyway (see: broad preference for milder tasting coffee over super-strong medium-roast with sharper, fruitier notes). Some styles of wine are somewhat more expensive in general, and in my experience usually taste better. Often regionally protected wines can fall into this category, e.g. Barolo, Chianti, Amarone. I don't really find these expensive, but I expect wine-lovers would tell you you can't find a $5 vino as nice as a $40 one. Beyond that it's quickly diminishing returns and status-seeking.