Savaria Dance Studio in Norwood, MA is one of many studios I know that got started by people who were just taking classes and decided it was fun to start a studio so they did.
Dance teachers are a dime a dozen so if you want to start a studio, go ahead. Its just like anything else, you don't need to be a chef to open a restaurant, you can hire a chef. Chefs are much more expensive to hire than dance teachers (from Russia). You can hire a dance teacher for $10.00 per hour. Arthur Murray Studios do.
Go for it. Think of the negative side, you will have an empty studio to practice at and it is still cheaper than going to someone else's studio.
Good luck