The colors on the map seem to have more with where there are major metropolitan areas, big cities tend to allow people to make big bucks. Because top earners pay the lion’s share of taxes. There is no opportunity to make the big bucks in Albequrque, so they pay almost no federal income taxes. My guess is this isn’t a redstate blue state issue, it is a progressive income tax issue. Half of all households don’t pay federal income tax, you have to have some serious high earners to make up for that. The rural republican states just don’t have that high income tax base that major metropolitan states have.
Maybe this is an argument for flattening the tax base…
This is not the whole reason, but I would suspect it’s a biggie.