That was common practice in the last crash, at least in the IE. I had at least a half dozen people on my street do that in the early 90’s. When the builders started selling new homes at 40%-50% off they all bought new bigger homes that cost way less than the ones they were living in. Then they just let the old ones go back to the bank. There credit was toast for a few years, but really, how much does that matter if you have a home and a few credit cards already. You’re gonna get hit with higher rates if you buy a car but other than that there are few problems.
It’s would not surprise me to see it happen again.