While I agree that certain things at Disney do carry a premium just because they are Disney and the prices have gone up over the years, I do think there are ways to find value in a trip.
I have a family of four with two kids under 7. We can (for now) stay at a value for what I consider to be a reasonable price. The kids share a bed and my wife and I share a bed. We're barely in the room when we're at the parks so we don't need a lot of fancy. On our last trip we talked about staying on the monorail for some convenience but the price for that is very high.
We think the value resorts and staying on site provide a value even at full price for a few reasons. We like being able to get the dining plan. For us knowing that we have 90% of our trip paid for prior to arriving is a nice feeling. Yes there are ways to achieve the same with gift cards and the like, but it's not quite the same. Also, if we fly then we don't have to drive. If we stay off site then we need a rental car plus have to pay for parking. $14/day for parking plus $500 for a week of rental car almost covers the cost of the hotel completely. If we drive our own car the savings isn't as much, as we just get the parking fee covered, but I still consider that when looking at options. The girls also consider it a special thing to take the buses as well.
Lastly there is the emotional aspect of it. When you are staying on site you are fully immersed in the world of Disney and are truly on a vacation from the rest of the world. The hotel lobbies don't have CNN or ESPN running. You don't see the typical corporate logos (with the exception of Starbucks I understand) all over the landscape and you really can escape for that period of time you are there. And most importantly, since my girls are still small, they believe in the magic. They believe that the folks in costume really are the characters they are playing and it brings to life the movies and TV shows they love. These are experiences and memories they will cherish forever and will eventually pass down to their children. You can't really put a price on that. On our last trip we stayed at AoA LM and we were in the Ariel building. We put little gifts under the girl's pillows each night and told them that Ariel left them during the night. When we saw Ariel later in the week the girls, without being prompted, thanked her for the gifts. She didn't miss a beat and played right along with it. There is no way you could ever convince my girls otherwise that Ariel wasn't real and didn't leave them the gifts. That is a special thing that you don't get at a Marriott.
When my girls are older we will likely look into some other vacation options a little more but while they are young we will take these experiences as we can find them. Of course, your mileage may vary and what works for us may not work for you.