It's also a sign of folly for some. Many people hate-read the Sunday Real Estate section. There are often one-bedrooms listed for $700k – $1 million, with $1K+ per month maintenance fees. Add on to that $200 – 1K per month in taxes, and suddenly you will have to wait a VERY long time to make anything like the return you'd get from investing in a Vanguard Total Market Fund and renting for $3K per month.
Everyone in the real estate industry loves purchases because of the fees associated with purchase. But buying is often not a good idea (though it depends on when). If we get another real estate crash and prices drop by 10 – 20%, buying may start to make sense again. In 2011 buying was a great idea.
This same basic dynamic plays out in many cities. The NYT has a decent rent-vs-buy calculator: https://www.nytimes.com/interactive/2014/upshot/buy-rent-cal... that can help answer some questions. Notice the investment return expected, which is a vital part of these calculations.