Well granted Vauxhall / Chevrolet doesn't scream luxury, but I was more talking about the environment to be honest. It's a cut throat, commission based, world. Lots of pressure to make a sale, little pressure to be a team. Now obviously if you own the place then you can angle it how you like, but just be wary of what it'll actually be like. Some people no doubt thrive in that environment, but I'd say many more would not. Go in to a car dealership and ask to shadow someone for a day, might be worthwhile to get a taste of it.
Also, if you're planning on being a franchised dealership (i.e. lets say you're a BMW dealership), then sure you can own the place. That's fine, you own it. But expect to be strictly instructed on everything from the models you stock to the paint on the wall. From the signs you hang to the advertising you do. From the people you employee to the carpets on the floor. Everything is controlled, so bare that in mind if that was your aim.
Furthermore consider the cost associated with owning your own dealership. I can tell you for a fact more often then not the actual owners of car dealerships (not the people that run them, the owners), are rich people who have invested in the land and see this as a way to earn a bit extra while their land investments rise in value. It's not an easy thing to own your own dealership, you need a large space (consider not just the showroom but the car park where you will store vehicles) in a popular, client facing area. Not a cheap investment.
All in all my opinion may be very different from yours, so don't let me take away from your goal. I'm just trying to nudge you towards giving it a try before you make a big life choice is all
As others have said, regardless of what you decide to do for your career, the degree will always be good to have.