i doubt rental vacancies can be used as a bull or bear case for property
high property prices means less people can invest in property
higher rents/lower vacancy mean there is more competition in the lower end
this could mean a yield investment in the low end of the market is a good choice for now and a capital growth investment in the high end a risky choice
eventually this situation will completely soak up all discretionary income and soon we will be a nation devoting all our time to servicing our living costs. Oh what fun!
then when an economic shock comes along, such as low commodity prices/ high unemployment or something else, then what?