It's a comparison, but I wouldn't say a better one. You can't just rent a fraction of a property without sharing it with someone else, so the comparison is "What does it cost to get a place of your own in 1968 vs today?" and the answer is you either rent today's bigger but more expensive property, or don't - even if you could afford a 1968 property today.

As Adam Smith observed, when people get more income it almost always goes to better places to live. Better can be more space, better location, or more luxury in the space.

You can still find apartments built in the 1950s that are functional (places where the maintenance was done so they are essentially just as good as 70 years ago) and the rent is cheap. Most people want better.

The more interesting information on that page to me is that the living space per capita has increased. I was suspect that while square footage may be increasing, that could easily be offset by the number of people living in those houses but that doesn't seem to be the case.

The key information missing here though is a more generalized cost of living space per person, beyond housing. This data can still be biased, in general, because it may be the case that fewer people own homes, say more successful wealthy people, while the majority are renting these properties. I have a bucket of anecdotal examples of friends who still don't own homes in their 30s and are still renting.

This data would exclude all of those people painting a picture that people are doing well while some unknown population is renting, paying more per square foot than owning, and rates could be increasing per person per square foot over time. That population could be smaller or larger than those who own homes. I'd be interested to see those distributions of renting/owning and a similar cost comparison for renter square foot costs per capita.

Most renters are not renting "New US homes" and rent does not buy a house. It's a pretty poor comparison.

If a young millennial cannot afford a small apartment, it's a poor consolation that house sizes have grown.