A RE Theory from a Calculated Risk Posting

I was reading something of interest, related to earlier RE posts, on calculated risk (one word @blogspot.com):

"As the U.S. housing recession enters its fourth year, there’s no sign of a recovery because speculators account for most of the rise in sales.
...
While the purchases are trimming the inventory of unsold properties, most of those bought by speculators will likely return to the market when prices rise again, hampering any recovery, said Nobel laureate economist Joseph Stiglitz and Yale University Professor Robert Shiller in interviews.

“We’re creating a shadow inventory of homes that will be right back on the market as soon as the economy and the housing market begin to improve,” said Stiglitz, a Columbia University professor of economics. “We could see a double-dip in the housing recession if that happens.”"

(http://www.calculatedriskblog.com/2009/01/speculators-or-investors.html)

What I find interesting isn't that speculative investors have bought up all that inventory that disappeared in the fall, but that some fraction of that inventory--at the lower end, I imagine???--as rock-bottom-priced real estate. I've seen some great deals--the one on Glendale springs to mind, and that seems to be a rental or a owner-residing fixer-upper now.