At any point in time, there’s always some stock from every sector that gets short recommendation. So your first statement doesn’t mean much.
When you say every housing decline of more than 20% led to a recession, how many time is that? Why is Vietnam and Korean War period any difference? Why was it different that cause it to to crash as well? One major difference I can see now compare to the last recession following real estate crash is global economy. The economic landscape now is very different that it was in the past. Sure housing price decline will cause people in US to spend less. In the past, that would/could cause a recession. However, American companies are no longer selling only to American. They’re selling to people around the world. The question is, how much decline in American consumer spending will occur this time and how much increase in consumer spending will other countries experience? Will it be enough to offset the decline in the US? Only time will tell but as I see it, nothing is a sure thing and there are plenty of factors that’s different now compare to the past crash.
Oh, and if I remember correctly, the last recession was during the .com crash. Although that recession was short lived due to the major drop in interest rate. tech stocks were hammered but other sectors thrived.