That would definitely look impressive.
But the owners would still have all of the money from season ticket holders and luxury suites. I'm not sure what the walk-up total for Pirates games is, but I can't imagine it would hurt the billionaire owners very much.
Plus, I think the idea is to build some camraderie among the fans. My guess is that it's not very empowering to sit at home with your already paid for tickets going to waste. But if you go to the game, talk to other fans about your frustration with the team, find there are plenty of people like you - well, that's a different story.