I don't give a shit if the spa owners are smarter than me. There will be people smarter than and there will be some people dumber than me. At the end of the day, i only care if i make a living that able to support my lifestyle.
I guess you are not as smart as the spa owners either since you don't open a spa yourself. Based on what you said, you could have double your money if not more in a year time. Either you are stupid or too chicken to open a spa yourself.
A business owner always attempt to maximize the profit and minimize the cost.
Spa girls open spas because nobody is interested in a spa girl when they get old. They still to make a living. They are no different athletes. Some will become coaches after they past their prime in their sports
If the spa industry is so lucrative, there will be more spas.