Should Democrats be concerned about maintaining their margins in urban centers?

[It’s so Joever]

No, because this reduces our geographical disadvantage.
We should still campaign in these places and try our best to get as many votes as possible, but the current geography is awful for Dems. These new shifts aren’t a terrible thing if we can balance them out with other gains.
If anything we should prioritize doing better in Mid size cities/towns in smaller states such as Boise, SLC, and Anchorage where the city itself is large enough to determine the state.

[It’s so Joever]

Detroit is one that I would defiantly keep my eye on

Keep an eye on Cleveland. It isn’t a swing state, but it could be very revealing.

[It’s so Joever]

No, because this reduces our geographical disadvantage.
We should still campaign in these places and try our best to get as many votes as possible, but the current geography is awful for Dems. These new shifts aren’t a terrible thing if we can balance them out with other gains.
If anything we should prioritize doing better in Mid size cities/towns in smaller states such as Boise, SLC, and Anchorage where the city itself is large enough to determine the state.

For the sake of the House and Senate, that may be true, but if IL and/or NY become competative on the Presidential level for instance, that could cause some real issues. It could also revert GA to being red and basically any state where politics are dominated by 1 specific city gets redder.

Again, I am implying improved Dem suburban performances which should keep GA competitive. NY has a lot of room to fall although IL is concerning in this scenario.