I had a very wealthy friend once tell me "this big house is a joke. my wife spends all day every day trying to keep it clean and the 4 of us use the same 3 rooms unless we have a large party which is often"
Their house had an indoor basketball court. 6 bedrooms, theater, pool, 2 garages. Most of it never got used in day to day family life.
The recession changed my generation to invest in memories that can't be taken away by the bank.
I would also argue where tv changed the boomers and was a "time suck" social media is double that time suck amount. Meaning the millennial generation feels the entitlement and addiction to their social media and therefore don't have the "time" or desire to clean/maintain an extravagant and large home. Along with student loan debt that is through the roof.
I think this is a good time for landlords that can provide quality SFH at a reasonable price to allow millennials the lifestyle/home upgrades they want without the commitments of actual ownership and the struggle to budget for down payment on top of student loan expense, car payment, vacation (for instagram likes) etc.