I think the mistake is in thinking about it as a zero sum game. To be fair a lot of the people who I've heard make Sunbelt Exclusive arguments come from states that currently receive 0 national attention, and so could be forgiven for being aggressive in their quest for national resources. But I think a party that allows regional variation and evenly distributes resources is the one that comes out best.
I do like the idea of investing everywhere, but the party should still identify districts/states with the most promise and try to develop them with more resources than say, Wyoming or what have you. I don't think the party does a good enough job with this. They spend way too much money on advertisements/consultants and not enough on building a permanent + sustainable ground game that can also support organic GOTV in states that may not warrant as much financial help from national orgs as other, more competitive states/districts.
I'm not a believer in that the Democratic Party's status as perpetual minority party for the past couple decades was completely avoidable - I think the Republicans were eventually going to come out on top after the 80s, but Democrats have made things worse by not maximizing their potential. In fact, maybe maximizing isn't even the best word. Sometimes Democrats seem to shoot themselves in the foot out of stupidity or greed. Look no further than the issues with the DNC, and how that was all easily avoidable.
It's so frustrating.
Oh sure, the 'mistake' is being made by people sounding a full retreat (for reasons of their own), not you. Sorry for the ambiguity. Targets are fine on Presidential campaigns, but I don't think that the national party, particularly at the DNC, should be focused on investing large amounts of money on particular regional bets. Give nearly every region a relatively flat amount of resources so everyone can capitalize on opportunities they see in their region.
Heck, there's even a case for throwing a small amount of money at Wyoming every cycle. The fossil fuel industry is collapsing, the GOP doesn't really know how to handle that, and Cheyenne + Casper are growing. Why not give the state party enough money to get its voter file in order, hire a couple full time organizers, and see what they can make of it?
Maybe that wouldn't have saved the party in the Reagan Era, but it certainly would have softened the blow. At minimum, I think it would make it easier to bounce back from systemic setbacks. You'd have fewer situations like Alabama, for instance, where there's barely a statewide party apparatus (and what there is is deep in debt) statewide candidates can't raise money, &c &c. So the Joneses of the world have an easier time of it, and shifts in broader socioeconomic trends (ex Georgia) can be capitalized on by local forces much quicker.
As for parasitic consultants: yep. Though that said, various subsections within the DNC are also lending their imprimatur to some interesting projects I've heard rumors about.