I don’t look at it like that. As far as I know, each restaurant is considered a separate “business” with their own expenses, profits & budgets. There is no swapping of business dollars between restaurants. So Chef Mickey’s lost money that they were planning for at that point. Their staffing is set, planned amount food is being prepared. I have no idea how many last minute ADRs or walk ups happen at any restaurant, so no idea if the OP’s 8 seats are able to be refilled within 90 minutes of their time. Because it would probably be people who have no ADRs already but are looking for CM that would fill it. I have no idea if there are enough of those at any given time. Restaurants do send servers home if the place is slow, so enough last minute cancellations may leave them overstaffed or cause servers to lose hours & pay, to say nothing of lost gratuities even if they’re not sent home.
Sure, OP is only 1 party, but a big party. Multiply it by many times a meal period, because, why should the OP be the only one cancelling last minute. And I can see why Disney felt the need for a drop dead cut off for cancelling/ changing. How quick people are to go from “what a great advantage to be able to cancel/ make changes until 2 hours before” to complaining that they have to actually make their decisions by 2 hours.