I thought that I would chime in as I am in a similar situation. I own a profitable food franchise and I am also applying to school this fall. I understand the points being made, but I disagree somewhat. First, my opinion is that of someone applying, I have not attended bschool and therefore I am just speculating on the potential benefits, etc. Much of this conversation is dependent on whether or not you see a long term future in your business or if you believe that later on, you will be trying something different. If you can see making this business your life's work, then business school would probably set you back...pt may be a better option. However, if you are like me, and don't see yourself in that industry for a very long time, bschool could be very beneficial. Exposure to new businessess, ideas, people, etc. are all great reasons for an ent. type to attend school again.
I think many ent. type people become bored quickly. Many do not have the patience to see a business from begining to end. They enjoy the startup challenges of a young business, but then are off to the next challenge when the excitement tails off. Who is to say what is correct.
You need to assess what you want out of bschool. If it is to learn how to run a small business, stay where you are and maybe go pt or take some classes at a local u. If you seek the benefits I listed earlier or other intangibles that may not be acquired from the experiences offered by your current business, take a good look at bschool.
I like to think of it this way...for the cost of two years and a hefty chunk of cash...I am purchasing the POTENTIAL for better decision making and opportunities over the next 35+ years of my business life. This may not be a very economical way of looking at the decision, but I know in 10 years I won't be looking back and thinking that I wasted money and time on bschool. However, in 10 years I may look back and wish I had.
Since I am not sitting on my next business idea, I would rather take the chance to invest the money in myself. Your situation is unique, but don't be afraid to do something that you want to do simply because others have not taken that road. There is no standard pathway for an ent. I am probably rambling now, but those are my thoughts.