Sometimes they're overpriced (Miele is), sometimes they're expensive to maintain (try get a stain out of marble), sometimes they're not durable (think of cashmere sweaters). There is no secret sauce that tells you whether the price of something you buy is a proxy for its qualities. And when you buy something expensive, you're kind of pissed when it breaks.

That's why many wealthy people go for the expensive luxury shit at first, like buying a Porsche, or a 30k kitchen remodel, only to go back to good old Toyota and ikea kitchen, cause they're just as fine and a fifth of the price / maintenance.

You usually learn those things the hard way.