1. tax write off on interest. But with interest rates low, that is not as usefull as it has been in the past.
2. A few states such as texas, have some additional asset protection on your primary residence in case of bankrupcy
3. homstead exemption on property tax (approximately first $100,000 property value), varies by county.
4. property tax freeze above age 65.
5. some capital gains exemptions for primary residence.
but a store of value is a store of value. Would you be ok with people buying treasury bonds as a store of value ? Or would you incentivise higher risk investments, how ?
Also, private schools, golf and tennis clubs also price out a lot of people. Not too different from zoning restrictions.
Look no further than the BLM and leasing on public lands. Grazing, etc.
Land as a store of value is related, but different than housing as a store of value, especially in cities.
In the U.S., we've collectively done a lot, culturally and legally, to make real estate a principal savings vehicle for many if not most people, and this has had a lot of negative consequences. Zoning Rules!: The Economics of Land Use Regulation (http://www.amazon.com/Zoning-Rules-Economics-Land-Regulation...) by is a good introduction to some of them. Chapters 7 – 9 in particular explain how the 1970s saw the growth of zoning restrictions that have driven housing costs in urban areas relentlessly up.
I'd be curious about alternate land-ownership structures or incentives that make people view housing more as a service than as a good store of value. I don't know what that might mean in practice, but the idea itself seems important to me.