Home prices relative to incomes were low in the 1980s and the 1990s. Home prices boomed in the 2000s while incomes remained flat. Homes were cheap in the wake of the 2008 housing crash, but unemployment also went to double digits which made it hard for established millennials to buy homes. Home prices have essentially recovered now, and while jobs are easy to come by in 2018, wages are still low.
Those are the macro reasons why millennials can't afford houses when their parents could. It's not click-baity or sexy, but it is the truth.