Median household income seems like a pretty bullshit metric when talking about parts of the country where it's not uncommon for multi-million dollar ridgetop mansions to coexist with gross poverty. All of the high elevation country I've visited (disregarding obvious outliers like Denver and the front range) had a few things in common: very wealthy people enjoyed having homes there and the rest of the locals were dirt poor with no obvious opportunities for social or economic advancement.