Income inequality is at least as big of a problem, if not bigger, in blue states than red states:
https://en.wikipedia.org/wiki/List_of_U.S._states_and_territ.... New York is the most unequal state in the country.
I don’t know about gerrymandering. In the most recent Texas house election (Texas being one of the major ACA holdouts) republicans won a 12-point seat margin with a 7-point popular vote margin. The governor, which is elected by statewide popular vote, won by an 11 point margin. In the 2022 Tennessee House elections, meanwhile, republicans won 75% of seats with 70% of the popular vote, which is as lopsided as some heavily skewed states like California and New York. (At a certain point, winning more seats than popular votes isn’t due to gerrymandering but just normal population distribution effects.)
I suspect the real issue is that, in red states, the democrats tend to be low propensity and younger voters. In Tennessee, Trump beat Biden by 24 points. But the GOP beat democrats by almost 50 points in the popular vote in the 2022 Tennessee House elections.