That's the thing with a republic - those who vote Democrat in NYC or LA have to compromise with those who vote Democrat in other places like Virginia and Oregon, for the type of median representation they get in federal government.

Democrats used to have the South they could count on, and eventually the nation got FDR for four consecutive terms and the New Deal.
Then the LBJ administration - from Texas, of all places - and Congress passed the Civil Rights Act, and Democrats lost that electoral advantage they had in the South.

All the ingrained racist simpletons in society shifted towards the other side - "That republican fellow might screw me over, but at least he's one of ours, a good patriotic christian (read: white) American that talks to me in MY (racist dog whistle) language!"

What so many people don't seem to ever get is that permanent changes in Washington work through inertia and take voting in every election, because the safer any party can feel in office, the bolder they can afford to be in that slow-moving, change-resistant place.

Democrats did it before because they had the South they could rely on, including Texas. Now Democrats don't have the South.