As a licensed Real Estate Broker (in Florida) and a user of the Internet for over 25 years, I have holdings in both residential real estate and domain names built over the years. I have actually been in the position of trying to decide which would be a better use for my money. To answer the question, all things being equal - and they never are - shelter is always on the "MUST HAVE" list. Last time I checked, domains - even great ones - are on the "NICE TO HAVE" list. As a business, domaining is an exciting and potentially lucrative way to go. But if your mother in law moves in with you from another state, you can't really put her in one of your vacant domains for the month.
I do agree with the comments made about most real estate professionals. As pointed out earlier, many of them took advantage of easy credit, excellent earning power, close relations with banks and mortgage brokers, and a little knowledge to generate portfolios highly leveraged properties. Read 'flips'. I have no doubt that many of these opportunists will move on to other occupations in the near future, perhaps domaining.
Certainly the current domain landscape looks very similar to the real estate industry of five short years ago. As domain sales become more mainstream and the media picks up 'bought for a dollar sold for a million' rags-to-riches stories, we will see a huge influx of new domainers. THIS IS NOT BAD. A rising tide lifts all ships.
Bottom line real estate is a market driven for the demand for housing. Prices are a function of supply and demand. More people, more demand. Industry shakeout? Yes. Market collapse? Impossible.