The modest house where I grew up in the D.C. suburbs (1,150 square feet, three bedrooms, built in 1950s, okay school district) is estimated on Redfin around $600,000.[1] That's a $120,000 down payment. According to the article, millennials spend $3,100 a year eating out. Even if they cut that out entirely, it'd take them decades to save up that down payment.
The cost of housing and rent has gotten so out of control in major metro areas that the usual frugality tips don't make much of a dent. What good does cutting out your $4 latte out do (maybe $100 per month), when your rent is $2,500 month for a 1BR?
[1] My parents bought it in 1990 for $175,000. People in my dad's line of work certainly don't earn 3.5x more than what they used to back then.