Does a beaty salon owner need a license?

Not necessarily. Anyone can own a salon (a business). That person is not allowed to perform any services on anyone. You must be a licensed professional to perform anything dealing with touching the clients hair,skin and or nails.

Although the salon owner can hire stylists that are license to work in their salon.

This also varies by state on some terms,but by law anyone owning a salon that aren't license are not allowed to perform any professional services.

Anyone can purchase a salon business and or sell it.

It generates profit for them because stylist can rent it out from you and or just rent a booth to do their clients hair in.