That's not really reflective of the market in reality. Rent in a competitive market (I.E. anywhere people want to live) tends to hover around the cost to own, buying with 20% down, plus property tax and mandatory homeowners insurance required by the mortgage holder.
In fact, usually it's cheaper to rent than it is to buy with only 20% down and good credit.
This is because people do this calculation, come to the conclusion "it will cost us a little more, but we get to own our dwelling, our payments eventually go to principal (though this is rigged by the banks too), and hopefully the market goes up and we get equity"
Yes, the market fluctuates, particularly in economic crisis. But it teeters back and forth based on the costs to buy and rent. Because if rent exceeds the cost to buy, investors snap up property just to rent it out, and that raises demand on real estate to the cost goes up.