All this time people have been arguing that the DDP didn't change menus and didn't change portion sizes. You've just made the argument that it did and does. Free dining is only "free" to the patron. WDW and nonWDW restaurants get paid the same whether it is free or not. The only difference is in the mix of patrons. And with menus having already been streamlined and portions downsized, the other option left to do is to remove more expensive entrees when the mix of patrons tilts toward a higher percentage of DDP during free dining.
Excuse my snarkiness. The DDP did not cause changes in quantity and quality argument has always been a pet peeve of mine. No restaurant will continue to be profitable if they are spending more than they are being paid for a dinner. Restaurant servers are running ragged trying to keep up with the busy pace of the restaurants. WDW doesn't appear to be able to or perhaps doesn't want to hire more servers. Overhead is fairly fixed with the exception of profit percentage on food. Slash portion sizes and remove intricate preparations and you bring in greater profitability. Take expensive items off the menu when you are received a set amount of money per meal and you again create greater profitability.
Well, anyhow, it's moot. What will be, is.