I don't think there's necessarily anything wrong with being "in it for the money." Depends on how you organize your life and how you view your relationship to work.
For some people, their business is their life. They can't imagine doing something they're not passionate about. What they do for a living permeates every part of their life. For them to work at something they don't care about simply for the money is unimaginable.
For others, "work" is what you do to pay for your "life." If you can make enough money at this to support what you really love doing without spending 24/7 on running the business -- or spend a short time building a business to sell for enough profit to allow you the freedom to spend the rest of your life doing whatever you like -- then I don't see anything wrong with that.
The only thing is, more often than not, new businesses don't turn out to be wildly successful, and those that do succeed rarely do so overnight. Are you prepared in the event things take longer than you planned, or don't pan out at all?
If the new business doesn't turn out to be as lucrative as you'd hoped, or you find you can't sell it for enough of a profit to finance your dreams when the time comes, will you feel that you've been cheated, or that you've wasted a large portion of the prime of your life?
If the answer is "yes," or if setting up and running the business is going to take you away from the things you really love for a long, long time, then maybe you need to rethink the plan. But as long as you can stay realistic and keep an overall life balance, then I personally don't think it's necessarily a bad thing to be in it "for the Benjamin's" for the short term.