Like I said, I don't know about the US. It's a big place and you're probably taking too much of a "grand scheme of things" view here. Aside from geographical diversity, total % of home ownership doesn't change that fast – lots of older people already own homes, their children often inherit those homes. Houses aren't like hotdog sales and numbers change slowly.
What matters more is how much does an average 25 or 30 year old pay in housing costs? What hope does someone with a decent (but not exceptionally well-paid) job have of purchasing a house? A single % of home ownership across the entire population doesn't really capture that. Doubly so for such a large country as the US. I'm sure there are affordable homes out in the sticks, but also ... no jobs. That might work for the remote software dev, but not everyone is a software dev.
In Ireland the total housing ownership has fallen, but not dramatically. However, the reality for people not already having a home is quite bleak. Buying a house now is significantly more expensive than it was a decade or two ago, as is renting. I could buy an apartment on my own ten years ago with a salary that really wasn't all that great. I'd have no hope today. My rent today is about three and a half times what it was 15 years ago. There is a generation of working 20 and 30-year old who are still living at home because they can't really afford to move out.