Hey OP: If you were going to the beach for the day, and had lunch at a local restaurant, you'd probably drop $20. You might not see a single Bimmer.
At the 'fest, you get to see thousands of Bimmers, check out all the aftermarket manufacturers, and make some friends.
You're missing the whole point.
PS: 5000 people times $20 is $100,000 last I checked. That's grade school math...