It's a combination of things.
- record low mortgage rates.
- work from home is now very possible for many.
- many people are cashing in on the increased value in their current homes to upgrade/change to a different home.
- many people are retiring.
Case in point:
I have a sibling that is recently retired and not in good physical health. They can no longer do yard work or even moderate home upkeep. So they have to pay someone to do it. So, they put their home on the market and hope to move into a condo, where they do the upkeep for you.
House got offers within hours and a bidding war erupted. They got way more than they'd asked for, can stay in it free for a month longer, with very reasonable monthly rent until they find a condo. No deadline to get out! Wow!
So now the hunt for an available condo. Guess what? Every condo that comes up for sale gets sold the same day. Brutal.
This is the Indianapolis area, by the way.