From Fortune:

The housing market is being dominated by baby boomers, whose sheer number and financial advantage afford them a vast portion of the market leading to decreased opportunities for millennials to buy into the housing market as they face increasing rents.
Millennials are struggling to buy the houses that empty nesters currently own, and are being pushed into renting large houses by the dominance of baby boomers in the housing market.
Boomers hold half of U.S. wealth and much of it has come from the housing market, which makes it harder for millennials to buy and easier for them to rent large homes.
Since the 1980s, trillions of dollars have flowed from the public to the private sector, creating a massive wealth transfer that has benefited baby boomers significantly. Current conditions favor the boomers and limit Millennials’ entry into the housing market.



Read more: Redfin: Empty nest boomers own twice as many large homes as millennials with kids