Someone upthread mentioned the "normal people" like teachers etc.
Pay (relative to cost of housing & other economic factors) has changed a bit, but teachers/doctors/lawyers etc tend to earn above the average amount. If we think that a young couple with the income of two entry-level professional jobs are "average" then of course we're getting a skewed figure.
It doesn't matter if you're looking at twenty, thirty, or forty years ago. Most people before the age of 25 couldn't afford to buy a home unless they were earning the kind of money that is typical of graduate-level jobs (and Oliver's mum, they can earn money other ways, I'm just setting a benchmark here).
Most of my cousins are in their mid 20s. They are all saying that they can't afford a house unless they live at home for years first, have a partner with a good income, and then live with almost no luxury. Well, that's exactly what it has been like. Single people in their 20s, even baby boomers, couldn't afford a mortgage on their own. Couples in low income jobs couldn't afford a house as a couple. Rents are comparatively high and it takes a lot of hard work and deprivation to make the first step.
I think that somehow we've lost sight of just how grinding the early years can be, and have started to believe a media dream of early home ownership, life in our 20s being about fun, and having disposable income etc. Really, it's either or: really sweating it to get a first home (as a couple) OR having fun and spending money.
How the money breaks down is different, but the basic principle is the same.
Remember the phrase "life begins at 40"? That's because people used to spend their 20s scraping together every penny and trying to set up home. Then their late 20s/30s were the child rearing years, and their 40s would be the first time ever that they had a hope of some free time and some spending money.