I am supposedly in a low cost of living area. Last I looked at numbers, we were at about $65k dual income in an area of $42k median. Tiny stepping on one another 1000 sq. ft. house, $600 mortgage, one 5-10 year old car with payment and one 10-15 year old car paid off.This depends entirely on where you live. In a low cost of living area like where we live, a family of 4 making 75k can live in a decent house, drive a couple of safe, basic cars, send their kids to public school, and save for a Disney trip.
Also, as a PP noted this is really lower middle class. Middle class would extend to twice that income, and at that level Disney every year is easy for a family that is not over spending.
Went to Disney in 2010 at about $10k less income and paid $2200 for 6 days value resort, dining, discount, and no travel expenses added (drive). Beach in a 2 room oceanfront suite was about $1500 no travel expenses.
Looking at those same 2 trips, admittingly I looked about 2 years ago just out of curiosity as a coworker talked about it, with discounts Disney would have been $5500 and the beach (Myrtle) would have been less than $2400. There is no way I could have come up with $5500 to go to Disney and I don't believe people are booking higher resorts for 2-3 weeks for less money.