I agree that with 20 Luxury boxes, you should not be building anymore for a while, but you should absolutely drop the price of those boxes as well. Currently you have your price set at $800 a box, and you have it set to actually go up to $880 On July 3rd. You have 20 boxes, and are only selling 8 a game right now, why would raising prices get more people to buy?
Right now you are generating $6400 a game in revenue from those boxes. If you dropped your prices to $600 a box, you should pick up at least 3 new sales a game, if not more. So if that price decrease takes you to 11 a game sold, then your income from your boxes would be $6600 a game. Hopefully lowering the prices would generate more than just 3, but it would take 11 box sales to justifiy that price decrease.