That's a weird way to phrase it. Customers are always "subsidizing" businesses by paying for their goods/services. That's how businesses work, whether they're well run or not. What tips do is hide the cost of what you're buying. It was at least possible to calculate it yourself when everyone agreed on the standard 15% and only at places like dine-in restaurants. But that's no longer the case, so how much you're expected to pay is a mystery until you're handed the machine.