"my grand parent could buy their own house while only one was working, and a job that didn't require any diploma"
Yes, but they probably couldn't buy a house anywhere in the world they wanted. The house size was probably much smaller than the sizes of today's suburban houses. I would argue that one could by a small, economical home in the midwest.
"If they want to eat for the same price as their grand parents they need to eat junk food."
Again, look at the diet lifestyle choices of Gen Y versus their grandparents. My grandparent (I'm a Gen Xer) told me stories of eating onions for a month because his parents were migrant workers and they worked picking onions when they were in season.
Even today, it is possible to eat simply (rice, beans, in-season vegetables and fruits) for a low-price. You won't be eating much meat, and you won't be eating "luxury" items. But that is very similar to how people ate in the 30's, 40's and early 50's.