I believe MA put up his own money plus money from the team to improve the spring training facilities. I think the majority of the money came from the Brewers and MA and the city of Phoenix provided very little to the Brewers. My memory maybe wrong about this but I think it was mostly if not all of the money came from the Brewers and MA on this one.
I would hope MA and the Brewers would contribute more and I would also like to see the Brewers owning the stadium and everything else outright. I still think crowdfunding would be a better way to go for things like this. Get to throw out the first pitch of the game of your choosing (excluding opening day, holidays, season seat holder days and playoffs) for $5k. You could possibly sell about 60 of them for $300k and you could probably even bump that up to $10k and still sell them out at $1m. Sell the rights to name a bathroom for $1k. Get your name added to the walk of fame as a contributor to the funding of the stadium remodel for $10 (everyone would get this with any pledge greater than or equal to $10). Be able to take batting practice with the Brewers at the home game of your choosing for $1k (excluding holidays, opening day and playoffs). Become a Brewer for the day for $10k (includes uniform with name and a number of your choosing, interview with Uecker or Bill and Brian, signed baseball and you watch the game from the GM's suite). Could probably sell 10-20 of those.
There are more things the team could do to raise funds.