How many bass cabinets do you really think people sell? It’s not millions.
Things are priced by a sum of materials, labor wages, energy, taxes, insurance, machinery amortization, it’s a long list. It doesn’t cost $100 to make a $500 item. And then the end price is set by the seller who is responding to demand.
My grandma used to tell some story about going to a movie for a nickel and I don’t remember the rest because it’s a ridiculous story because the cost of goods and services angles up. You don’t want to live in a world where it trends down.