What difference does it make if they paid up front or borrowed it?
They actually paid for their share of the stadium up front, using their own money = they are able to use all current revenue (minus normal other expenses such as minor leagues, travel, etc) to support player payroll (minus other normal expenses, i.e. minor leagues, travel, etc.)
They actually didn't pay a dime for the stadium up front, instead using other people's money = they first must extract loan payments from current revenues (and then take out normal other expenses) before using said revenue to support player payroll
Why else do we still hear the "52% of revenues to payroll" line? None of their other expenses (with the probable exception of revenue sharing) changed dramatically when they moved to TF. The cost of running their minor leagues didn't change. The cost of travel for the team didn't change. The cost of their other employees didn't change dramatically. Why would payroll expenditures still be "around 50-52%" of revenue?