> Housing as an investment here references the idea of owning the home you live in being a great source of capital gains.
But why would you even want that?
Possibility 1: You want to invest $500k in housing, and live in one unit. You get one unit, pay the entire $500k plus interest yourself, receive no rent other than imputed rent, and then can't sell at the end because even if your property is now with $1M if you sell you get a huge capital gains tax bill while still needing somewhere to live, so your "investment" has left you stuck in a place where you can't afford to move because the capital gains tax would prevent you from selling your house and buying an equivalent one, or even selling it for a smaller one at a profit because the difference in their values is lost to tax.
Possibility 2: You invest $500k in housing, get multiple units for that price, live in one of them, receive rents from other tenants that compensate for a lack of capital gains while holding an asset with a stable value, can easily move out of your own unit because you're not trapped by capital gains tax.
Possibility 3: You have $500k to invest, put $25k into a house for yourself and receive the small imputed rent, put the other $475k into an ordinary investment fund because you don't actually like investing all your assets solely in real estate. You now have a more diversified investment portfolio that isn't heavily exposed to volatility in the local housing market, are still getting the market rate of return, are getting actual returns from the ordinary market instead of paying a huge amount in imputed rent and once again aren't trapped by capital gains tax if you ever want to move house.
The first one is clearly the worst one.
> The reason people care about this type of 'housing as an investment' is that it helps sell people on high mortgages, so more people can own rather than rent.
High mortgages are the counterargument. If you were taking out a $25,000 mortgage, that could be a good investment even if the value never goes up, because you get a place to live, and are insulated from (and indeed benefit from) potential increases in local real estate if there were any. If you're taking out a $500,000 mortgage for one unit, the imputed rent could be the same percentage of the investment if local rents are high, but now the potential upside is blunted and replaced with risk of value loss because you're buying high instead of buying low. That's a bad investment -- you're getting the same percentage ROI in terms of imputed rent while exposing yourself to the risk of a housing crash with a disproportionate share of your net worth in an undiversified investment, and further increases in value are long-term unsupportable by local wages.
And if you're talking about a matter of policy (we want to encourage home ownership) then there are obviously more people who would qualify for a $25,000 or $100,000 mortgage than a $500,000 one. Even for the smaller number of people who could make the payments on $500k, you don't have to convince them to take out a huge mortgage if you can supply them with the same house with a smaller mortgage.