General Discussion

The problem with that is there is a very clear policy purpose and interest in making housing an investment - the vast vast majority of people will eventually own a home, and it is a forced savings vehicle because people are REALLY bad at saving for retirement. Even if you fix our lack of a social safety net, home ownership is generally seen as a public good because it encourages people investing more in and caring about their community, being willing to pay higher taxes to support more services, etc. It's not a no brainer to make housing an investment (there are arguments against in a society with a good social safety net), but it is very purposeful through good public policy. It has little to do with the recent (very recent, relatively) buying up of single family homes by investment banks, etc, despite people implying all the time it's some secret cabal and shadowy wealthy figures doing it for their own benefit. Everyone sees conspiracies everywhere these days.

Of course, if we're going to say that home ownership is "good" and keep doing all the tax incentives for it, we do need to stop corporations speculating and driving up housing costs, and could do so by some targeted taxes on unoccupied properties in the same portfolio. But there's an argument to be made that that's a relatively small portion of the problem, since a lot of our housing stock issues can be traced back to single family zoning issues, as well as road and highway funding leading to suburban sprawl and unaffordable newly developed subdivisions while cheaper starter homes don't exist anymore...but either way affordable housing stock just hasn't kept up.