1) who that money is spent on is theoretically the responsibility of the front office. The owners give the budget and approve large expenditure
2) tap water isn’t “free”. If you live in a city, you pay city water bill, if you live rurally you own a well. It is cheap, but many cities subsidize the resident drinking water price with business water prices, ie car washes and stadiums pay a lot for their water so the residents pay a smaller proportion of the total water bill. All this is to say the bill you pay may not be directly related to the cost. Your Brooks Lee shirsey at the ballpark is the same on MLB shop dot com, and you can look at every team’s prices there. Not a lot of difference.
3) unlike football, baseball isn’t salary capped. Spending more doesn’t guarantee anything because there is a surprising amount of parity between mlb teams, but spending helps a lot. This 2019 article had 24 of 25 previous World Series winners had payroll in the top half of the league. The only exception was the ‘03 Marlins. https://www.baseballamerica.com/stories/world-series-champion-opening-day-payroll-ranks-in-the-wild-card-era/