this still wont work.
Heres why. Take Georgia for example.
You'd need all these black people to stop just moving to Atlanta or the main city of the state you're proposing for this idea. Democrats need to win all these red districts, not just the population. The population will let democrats win U.S. Senate Seats...but when it comes to the State Assembly, the state is still republican!
The state assembly of Georgia is still 2/3rds republican from ALL the districts run by conservatives. All democrats are packed into fewer districts.
This is why I'm kinda glad Stacey Abrams lost because she'd basically have been hamstrung by the State Senate and State House of Representatives, like North Carolina...and they'd overturn her veto on everything and make her a 1 term governor and cast her as a failure.
That's myopic. You claim the idea won't work, then base your opposition on a stipulation that wasn't even in our suggestion.
Why think Atlanta is the only place Black people can move to? I'm a HUGE advocate of strengthening rural Black communities, of encouraging more small-town and small-city living as opposed to dense urban, and of more Black people both buying land and/or getting into farming. The # of Black folk (and scattering of like-minded non-Black folk) that it would take to flip a lot of those districts isn't large. Especially considering that some of the racists will helpfully move out when Black folk start moving in.
You've already given up on bringing poor whites back to the democratic party, but you also want to abandon all rural areas to them? You've already pointed out the legislative difficulties that poses, and not just in red states. Not to mention that city life tends to be worse for physical and mental health in addition to all the social pitfalls our kids face there.