You are correct: things are not worth a certain price because they work or someone merely says they a worth a certain amount. They are worth the price because someone voluntarily paid the asked amount. It is why your services, whatever you do for a living, are worth what you are paid. This is basic price theory.
I understand price theory. Would you like to buy some of my 100 dollar toothpicks? they work well.
If you would like to defend the indefensible by saying whatever anyone can charge is “worth” it than fine. I would prefer to expose every snake-oil sales tactic in the world, the monster’s the bose’s, the clinton’s, etc.
If people buy monster cables we let the terrorists win.