Well, I can say from my experiences that guests are treated differently based on their type of ticket at the entry point. When I was an AP holder, I was treated like family. CMs made small-talk with me and my kids were always referred to by character references. This past year, we dropped our APs, but I have taken 3 1-day trips, one with each of my children. The CMs at the entry points were kind of rude comparatively (still very nice, but it was different). They made a point of telling us all the rules and weren't as sociable.
In terms of APs, grad nite tickets, day-trippers, and long vacationers, I do think there are differences because of the nature of DL. It's been a "locals" attraction (I define that as people who can drive there in less than 3 hours) for a long time and that history does show itself. WDW is more pushed for long-term vacationers because it's a comprehensive package and there's simply more space for tourists. CMs, once you're in the park, don't really know who you are unless you're presenting your AP for a discount, so it doesn't matter so much at that point unless an AP'er strikes up a conversation. And please, for the love of God, I'm almost certain grad niters fall at the bottom of the food chain despite what it may look like on the outside. As someone who has worked grad nites at other amusement parks, I'm pretty sure no one really likes those ticket holders except the grads themselves. But, it's not like anyone has a choice.
Anyway, yes, it's more expensive overall to come as a tourist with hotel costs and everything, but to me it's a choice you make knowing tourism in general is pricey. When I travel to WDW or other out of town/out of state attractions, I've noticed similar issues, but then, I'm a tourist. It happens. I'll tell you, I've worked at 2 non-Disney amusement parks and the same hierarchy goes for them.
EDITED to add that as someone with experience in this sector at other amusement parks, I can say with little doubt that the majority of revenue at most parks is AP holder or day-visitor revenue in the form of food and merchandise. Ticket costs typically are mostly allocated to paying for the permits required for rides and attractions (at least at the parks I worked at), so the actual net revenue ends up being lower than you'd expect.