As a kid growing up in Anaheim in the 70's and early 80's (and a 10+ year cast member in my late teens and 20's), we went to
Disneyland as a family once a year. We might add a visit for one of the many night time private parties they had back then (an aunt worked for B of A and an uncle was at Xerox), but that was it. Other vacations were road trips up and down California with nights at Motel 6 for me, my mom, dad, and two sisters.
We were by no means "underprivileged". We went to parochial elementary and high schools and our dad owned his own plumbing company. Even in the late 70's, a trip to Disneyland (a literal 5 minute drive from home) was not a casual affair, and there were LOTS of kids in Orange County that didn't see the Park even every 3rd or 4th year (or ever). Kids in Anaheim, Santa Ana, Garden Grove, etc. who's families just couldn't afford to budget "trips" to The Happiest Place on Earth (in fact, one of the poorest areas of Anaheim back then, the Jeffrey-Lynn neighborhood is right across the street from the DLH). Back then, there were tons of discount tickets available too for schools and other groups and often times that was the only way a kid would get to go to the Park, and unless their parent was a chaperone, they may have been going to Disney WITHOUT their whole family. Oh, and we ALL had a drawer or box at home filled with all the unused ticket books because you weren't letting THOSE go to waste.
I guess I bring this all up to illustrate my belief that a Disney trip (whether it's a day trip to Disneyland, or a week-long visit to WDW for a family from Omaha) has never been a simple matter for many, of just waking on Saturday and heading off to see the mouse. I have a strong feeling that it's not a question of whether Disney has grown too expensive for the "average" family, but more has it become too expensive for "my" family, and has been stated above much of that depends on how YOU like to do Disney and how OFTEN you like to do Disney.
I also feel there may be some serious rose colored glasses being worn by some folks. While I remember the trips most vividly because I'm the oldest, my youngest sister couldn't tell you one thing about budgeting, how often we did or didn't go, getting our hands stamped to go outside the Park to eat dinner, etc. For her, they are just Disneyland memories and fading photographs. I wonder how many people going to DL or WDW today really "remember", personally, what a Disney vacation really entailed, cost-wise, 25 or 30 years ago.