That sort of thing should end with the end of low interest rates. When interest rates were near zero, borrowing money to purchase unused real estate could be profitable if you could sell some of it. No longer true.
Right, unless those flippers paid with straight cash, they are going to have a hard time raising more money to buy more houses, and they might go underwater on the current ones.
To see what that looks like on steroids, China's economy is at real risk of recession due to property developers running out of cash and failing to build promised developments. (Most apartments in China are purchased before construction starts, so you can buy a house and not end up with one in the end.)
The average time to flip a house is 45 days to 6 months. Let’s pretend it’s going to cost $500 more a month in interest rates, that’s only $3000 more dollars. If you could do 3 in a year you’ll only lose about $10k.