This is a comment about exceptions:
A 30-something friend who grew up going to WDW just told me that her 23 yo sister just bought her own contract at Poly, direct. 50 points, and she definitely wanted Poly to stay at Poly. Paid cash as she'd saved it all, has a good job, no bf, kids or fiance on the horizon, and her parents own at BWV. She has the flexibility and ability to plan 7+ mo out and go at off times, and will only need studios for the next several years. So buying direct makes sense for her.
I had to laugh when I got to that part... We get to $750 easily!
The last time we got TiW, we did multiple character meals and signature restaurants, and we were always there at the same time as friends (sometimes planned, sometimes not). On our first trip out of 3 with TiW, we did a dinner at Akershus for 5 adults and 3 kids, add in the adult beverages and we were more than halfway there on one dinner alone. On our 2nd trip we did an adults only dinner for 6 at Cali Grill and ... you can do the math.
DDP never made sense for us, because we usually average 1.5-2 TS meals a day, don't eat 3 meals a day, and don't do much CS or snacks. But it's definitely important to know your own travel preferences. We tend to do at least one TS meal a day, often character meals or signatures, and those are an integral part of our vacations.