It is hard to "horde" a large amount of capital. I would say there are only 4 ways it can be done:

1.) Invest in a natural monopoly. That's fine, but most of these are highly regulated (e.g., utilities) and limit your returns.

2.) Invest in real estate. This is rent seeking at its finest. Henry George [1] addressed this issue, but his ideas have not been widely implemented (unlike Marx).

3.) Invest in government debt. I'm always surprised that people like Krugman and Piketty never bring this up, but the fastest way to reverse inequality would be to default on the national debt. The debt is just a transfer payment from tax payers to wealthy debt holders. It is almost like Feudalism.

4.) Buy and hold a nonperishable commodity.

Even your example, the housing market crash, is not an example of hording. In fact, it is the opposite. It is the squandering of capital. Piketty might even argue it was a good thing (like WWII) since it reduced inequality. Or at least it did until the government intervened.

[1] http://www.henrygeorge.org/whowashg.htm

My fault for insinuating the housing crash was an example of hording. Clearly it was not. I meant that sentence as a critique for the statement in the article that the free market necessarily produces a rational investment.

A priori, no investment is "rational." That is, was the construction of 100,000 tanks to export the Communist revolution a rational investment by the Soviet Union? How about the $2 billion in private equity that went into building Facebook, a system designed to let people "like" their friends? The point of a free market is that many experiments are run in parallel. Some of these are deemed rational via feedback. Some fail, and are deemed irrational. A free market is not more rational than a planned economy; however, unlike a planned economy, a free market isn't dependent on a single plan.