They are not being bought by regular people like you - they are being bought by investment companies, hedge funds, and filthy rich investors... all for the the sole purpose of turning them into rentals.
By turning them into rentals, they keep supply low which increases prices... which prevents people from buying, keeping rental demand high, which also lets them charge exorbitant rental rates. They are gaming both sides of the system to ensure that us peasants can be milked dry over a fundamental human need.