What's the urban environment around the stadium?
I think Wrigley only has one unpaved parking lot with only a couple hundred spaces. After that, if you insist on driving to the game, you have to find municipal or street parking and walk.
I don't know how things have changed in the last year but according this
Washington Post article the blame isn't necessarily with the team ownership but the D.C. city council. The original stadium agreement terms has the city creating 1700 parking spaces and they've not done so.