The percentage of housing sitting empty is quite low, and well within the range for any asset. 100% utilization is not a realistic expectation and would not be a healthy situation. Markets need the flexibility of owners being able to wait before committing a resource to a particular usage.
But there is artificial scarcity in housing, and that's almost solely down to regulatory restrictions that suppress private property rights, whether that's rent control that make it less profitable than it should be to invest in housing, onerous permitting processes for building a new house, or zoning restrictions limiting the density of a new housing development. Economists have chronicled the problems created by these interventions, in detail.
But there is artificial scarcity in housing, and that's almost solely down to regulatory restrictions that suppress private property rights, whether that's rent control that make it less profitable than it should be to invest in housing, onerous permitting processes for building a new house, or zoning restrictions limiting the density of a new housing development. Economists have chronicled the problems created by these interventions, in detail.