Actually there were plenty of restaurants that did, however there were some that did not. We CHOSE to visit both, bit when we were required to order an adult entree for Kady because of our choice, we did. You can do the same in reverse. Visit restaurants that do not force your 10 YO to order from an adult menu. That means you avoid fixed cost restaurants that are age based.
Again, you are personalizing this.
DDP or not, you have choices. You go to restaurants that your 10 YO can order off of the kids menu, stay away from those that do not. You keep fixating on age, however there are a number of people whose dietary concerns are not age based but medically necessary. They pay adult price even if they use a feeding tube if they are 10 and older. The alcohol was a bonus. the price increased $1, and you can order all kinds of specialty beverages. Fair is fair. Everyone 10 and older pays the same price. People 9 and under pay a reduced price.
You really need to determine what works for your family. The plans are not for everyone. The buffet and character restaurants really are not for everyone either.