It's pretty much impossible for just 1 HBCU to move up to FBS alone, but moving up as a conference can be done. There is strength in numbers. The problems that Bama St. and FAMU faced had a lot to do with not having the money to sustain themselves as an independent, and not to mention no FBS conferences were offering up memberships to them either. The entry fee to join as a new member would cripple their operating budgets and quickly reduce them to bottom-feeder status. Mounting debt would force them to still take money games against the same teams they would've been playing in FCS, but they're fans/alumni would demand that they keep their HBCU rivalries alive.
But as a conference, 1) there's no entry fee for being a new conference member, 2) you only have to win 6 games in order to become bowl eligible (just win your conference games and you're in there), 3) now multiple teams are playing in multiple bowl games getting paid money. Split the sum amongst the other conference members and we're all growing our budgets, 4) attendance-wise the conference will be fine (15k+ avg. requirement met even though a lot of current FBS teams are failing to meet that mark). 5) Even scheduling would be a breeze. 8 conference games and 4 OOC games, and now because you too are FBS you can schedule a home and home with P5 if you wanted. Imaging AAMU/ASU playing a Tennessee or UGA at home, or JSU/Alcorn playing Ole Miss or LSU at home. And you're still playing your in conference games. Revenue would not be hard to find. Now, you can pay your coaches more competitive salaries.
It should be no secret that a few schools in the SWAC already have/had FBS in there sights (FAMU, JSU, and Bama St.) based on past attempts and/or current expectations. Some other schools in the SWAC haven't expressed interest but could make the jump if they seriously committed (SU, PVAMU, Alcorn, AAMU, and GSU). Each school has a few things they'd need to improve upon. I think the largest jumps would have to be made by the remaining 4 (TxSU, UAPB, MVSU, and BCU) because of the financial strain they would have to endure, but like I said before there's strength in numbers.
Now's not the time to be flat-footed and maintain the status quo. People are ready for a move like this. If we formulate a plan now and work towards it as a collective, we'll get there in 10 years. Don't be caught looking stupid when FAMU or JSU announces that they plan to leave the SWAC in the next 5 years. Deion already has it the scenario written into his contract. Think about it.