When you see a doctor, why do you pay money? Experience, expertise, training, and good advice.Its highly offensive to suggest that there is any expertise involved in screwing a pair of drivers into an mdf box. Where is the expertise in that?
There is nothing wrong with earning money by making speakers. The question you can't answer is this. At what point does a speaker become overpriced? What you seem to be suggesting is that no matter how high the price is, as long as someone is willing to pay for it, its reasonable. Its people like you that have made hi end audio so horribly overpriced. Not only does this make it unaffordable but it promotes scamming.
Healthcare is a horrible example to use as that is just another area where people are being overcharged for little work.