Here in NZ there are suburbs of ghost houses which are built and owned primarily for the purpose of speculation- they are sometimes used for rental like AirBnB or just left empty- they are high spec and often debt leveraged. IMO a large part of the housing crisis is due to housing being used as a speculative SoV commodity...certainly here in NZ where CGs on housing are not taxed...and almost certainly in other economies where housing can be a better safer SoV than other investments. A lot of this goes back to 1971 and to the later neoliberal deregulation of banking- which allowed commercial profit motivated bankers to isssue new fiat debt toward any purpose, not just productive purposes as was required prior to the neoliberal 1980s 'reforms'. In NZ the ratio of non productive lending by commercial banks has gone from close to zero to over 60% since the 1980s and most of that non productive debt is secured by housing assets.