I'd argue the complete opposite going forward for real estate. There is supply as far as the eye can see (plus the enormous shadow inventory), tons of people who have too much house who'd like to downsize. Tougher mortgage regulations (for the massive amount of mid-upper end inventory), a shrinking middle class, a bloated and desperate public sector that will fight tooth and nail against property re-assessments lower, continued pressure on wages, and a growing level of resentment for those who DO pay their mortgages vs. the squatters and strategic defaults group.
Once you take ownership of a group of properties you are at the mercy of the local tax assessor who can just pull a number out of a hat and declare your property taxes should jump x percent. All of a sudden that great investment turns into a noose around your neck. As we've all seen clearly these past few years, economic realities are of no concern when the unions need their pensions funded and the local school districts decide they need their pay raises. They could care less if your house has declined 30% in value, all they know is that they have to get paid and so be it.
Why put yourself in harm's way with all the trends working against ownership.