I know the red/blue model is useful in some cases but I live in a red state (Louisiana) in one of the most blue cities in America (New Orleans). Biden won like 40% of the statewide vote and we have a two-term Democratic governor (about to leave office but still). And that’s with a state Democratic Party that is a constant mess, never has resources, gets zero national investment or attention, and sometimes doesn’t even field candidates.
National politics isn’t everything. Sure, Biden shouldn’t spend much time or money here but Democrats have no excuse not to have an aggressive 50 state operation. Just having a credible candidate means a scandal can flip a Congressional seat but attorney generals and secretaries of state matter too. There’s even value in losing an election even if your candidate is just on the local news calling out his opponent.
Incidentally, I was in Atlanta a few months ago, and I saw fewer Confederate Battle Flags than I did in Indianapolis. Fuck Indianapolis, Atlanta is cool.
And then you have blue states, like NY where I live. I live in a blue section within the state, but I could travel a half hour away and end up in an area so red that they fly Trump flags, Confederate flags, and vote for Elise Stefanik. (I get TV commercials for her despite not being in her area.) That area might as well be the deep south despite being in Blue NY.