You're equating revenue with cost. Just because Amex charges $50 for a guest doesn't mean it costs them $50. My usual Centurion lounge visit probably costs Amex maybe $5 in actual consumables + whatever the pro-rata share of the fixed operating cost is (which I don't know). You should ask your kid what Amex's cost for MRs is. I would be willing to bet that their fulfillment cost is substantially under 1 cpp taking into account their bulk purchase agreements with Delta and other partners, suboptimal redemptions on the part of customers like statement credits/gift cards/etc.