Housing units per person really has not moved much since 2000 either way. We're basically near the median for the 20-year period.
https://fred.stlouisfed.org/graph/?g=j9kB
One big issue not stated in the graph however is that the amount of childless people and people living alone is up, so we require more housing to match changing preferences.
My wife and I are looking for a house, and the lack of options is extremely dispiriting.
It's a shame we can't compare to 1920, 1950 or 1970.
We only started collecting information on housing in 1940 [1]. That's why household data only go back that far [2].
[1] https://www.census.gov/history/www/through_the_decades/overv...
[2] https://www.census.gov/data/tables/time-series/demo/families...