Sounds like a very poor investment.
Over a period of, say, 35 years, even if you're achieving a return of only, say, 7% per annum, $100K will double every decade, thus becoming approx. $1m. (I personally have maintained an average of 10% p.a. since 2002.)
Of course, you can't live in stocks and bonds. But then neither do they ever require a new water heater, resurfacing of the driveways, or suffer hurricane damage.
One of the other problems I see with owning extra houses is the people who talk about how they paid only $150K and sold for $400K always say they made $300K. If they paid cash for the house and forget the property taxes then they can legitimately claim that. If they took out a mortgage they never seem to realize how much interest they paid over 15 or 30 years.