For the rest of my anecdata: For folks I know living in their own households, about 20% have it paid off. About half of those folks own multiple homes.
Sure - if you're 25 and most of your friends are aged 20-35, probably <40% even own a home. And those that do are probably <10 years into paying it off.
Hell, a few years ago when interest rates were zero I heard a lot of people saying it was a bad idea to pay off your mortgage early, and far more sensible to invest the money instead. So even if the people your age got a big cash windfall, they might not have paid off their mortgage.
On the other hand, if you know a bunch of 65-year-olds who've had maybe 40 years to pay off their mortgage, and 40 years of inflation on their side shrinking the principal? It's probably a different story.