Prop 13 is certainly unfair policy, but is almost certainly not a causal factor.<p>New York is a great example of a place with runaway train property taxes and perennial housing shortages in the NYC Metro area.<p>Property tax escalation creates vicious cycles, vaporizing buying power and creating disincentives for property maintenance, especially in older houses and poor neighborhoods.<p>In those areas, government aid programs create a housing price floor, so property owners maintain the minimum requirements for habitability, run the property down to zero value, and walk away.