Homes in metropolitan areas with tens of millions of immigrations have rising prices, but rural America is very affordable.
Millennials also do not start working at 16 or 18 like most of their parents did, so they delay their income too much into the later parts of life.
Rural America also isn't where the jobs are, though. By and large, anyway. Some decent income jobs can be found away from major metros, but some millennials own houses too.
I suppose a bunch of millennials could afford homes if they worked in the city and commuted from beyond the suburbs. But this isn't really empirically analogous to what our parents experienced. Not making a value judgement here on who "had it better", it just is what it is. If you want an explanation as to why millennials don't buy houses, it's wages, median home prices, the great recession, and probably that fewer of them want homes. We're also not having kids, so I hear.