Millennials can live at home because average home size has increased. My first house, built in the late 19th/early 20th century had indoor plumbing retrofitted and would fit in the garage of my current house.
And it’s likely not purely true. Home sizes being larger is also a function of REITs and corporate ownership of more consumer real estate, as well as boomers using soaring retirement fund profits to finance remodels, etc.
It’s way more complex than to draw any conclusion that this means purchasing power of homes has stayed close to wages. It hasn’t.