Not to burst your bubble (so to speak), but every short seller and retired hedge fund "guru" is spouting the same talking point about a "real estate crash" as if he came up with that theory all on his own.
But why look at theories when we have historical facts. We've seen, in just the previous generation, the entire systemic collapse of the American Savings and Loan system. It was the 1980's, and real-estate speculation had created a bubble in commercial real estate. The eventual real estate crash drove localized commercial real down some 50% in the areas hardest hit, while the national average turned out to be something like a 3% whack off of commercial real estate average prices. Presaging this collapse was a spike in unemployment, inflation, and an increase in the percentage of homeowners who were more than 30 days late on their payments up to some 6.5% of the mortgage-paying population.
Now, if you are TRULY worried about a modern real estate collapse, what you should be interested in tracking are the figures for current unemployment as well as the percentage of mortgages that are more than 30 days past due.
If you don't have access to those figures then you aren't in a position to seriously worry about the problem. At best you would merely be repeating speculation from others.
If you do have access to those figures, then you'll quickly see that we are today nowhere near the dismal shape that we were in back in the late 1980's.
But I will admit that the world can always change on a dime. If those figures spike, then owning real estate is historically a bad idea. During that "crash", your investment might be devalued by as much as 50% for as long as a decade (worst case). It's happened before, after all.