My guess would be opposite to your guess. I'd bet that on most weekend Brewer games especially, a minimum of 40% of the attendees are from outside the metro area. Again, purely my guess. And every dollar they spend at the stadium or night they stay in an MKE hotel is a dollar that the city doesn't have without the Brewers. That also doesn't cover the impact of, say, rural Wisconsin bars' revenue during seasons. Yeah, Wisconsin is a drinking culture, but I can't imagine that you have as many rears in bar stools on a Sunday afternoon if the Brewer game isn't on. Heck, I'd be super curious to know how many STL fans stopped caring about football when the Rams left, and the resulting revenue loss from football Sundays as fans stopped caring about the league, beyond just 'game' revenue.