CLT's local market is shockingly small. It's only slightly more than RDU. If RDU had more service at lower fares than CLT, that gap probably will be even smaller. If CLT can be turned into the mega-SE hub and BNA is on it's own way to a 150+ flight SE hub, why can't JetBlue turn RDU into it's own SE station at a much smaller scale? Obviously, it will take time and getting more gate access to even reach 50 to 60 flight. While JetBlue will never be connection oriented, they could connect more than they do now to win over greater market share.
Charlotte is only the 22nd largest metro area. It's not a tourist draw at all. I'd imagine companies either based there, or with significant operations are not in industries that book a large amount of corporate travel. No major colleges or universities or hospitals.
CLT is a major financial services hub and the HQ location for Bank of America. The city's top companies include Lowe's Inc, Duke Energy, Nucor, Brighthouse Financial, Domtar, and Sealed Air. Coca-Cola, Curtis-Wright, Bojangles, Lending Tree are some of the area's other top employers. CLT generates a significant amount of business travel but it's also a relatively low cost place to hub.
The idea that RDU could be turned into a mega-hub is simply idiotic. It would require the rapid build out of terminals, more runways, and would need to clear plenty of local ordinances to achieve that. CLT became a major hub decades ago, starting with Piedmont, then USAir, and now obviously, through the merger is the #2 hub for AA. I can see B6 building up some sort of focus operation at RDU, similar in size to what DL had there pre-COVID19, but with more service to Florida, California, and potentially, some beach markets, and focus that operation as P2P. JetBlue is overwhelmingly a leisure airline and derives a smaller (much) portion of its revenue from corporate travel, which, will not likely rebound to 2019 levels for a few years, but remains a key part of the RDU market, which needs access to Europe, Asia, and Latin America given all the bio-tech and pharma situated in and around the Triangle. That traffic will for the foreseeable future, flow via ATL, CLT, IAD, EWR, MIA, DFW, etc...JetBlue cannot offer that, not even with a pair of flights to secondary and tertiary London airports in the near future, which at the rate things are looking right now, will likely get pushed back well into 2022.