What I saw online the margins were a lot higher than 20% on alcohol sells, could be has high as 90% if you are doing it yourself, or getting a percent of 20 to 30% if you farm it out. What a lot of these pro teams are doing is they also own the company that they have farmed out the alcohol sells too. So the team gets a cut of each sell, and the rest of the money comes in from the other company they own, which then does not show up on the books for the team.
Our youngest son and his wife watched the ISU/KSU game on Saturday on some type of Vegas sphere deal they just opened in Dallas, I asked how much was the beer and his stated $10 for a domestic beer 16 oz bottle. I can go up to Fairway and get them at retail 12 for around $20 bucks, that is retail for me. That comes out to less than $1.75 a beer. If they are selling them at $10 a piece, they are not paying more than a couple of bucks in taxes and salary for the beer sellers, throw in overhead and you get a little more. They are making at least $5 a beer they sell, and they are not paying the same prices I do to purchase it. So that beer that I get at $1.75 at the store, a huge stadium is paying less than a dollar for.