Ten years ago, DFW was still considered a hub for DL with something like 20-30% market share. I saw a statistic yesterday that showed that US is now bigger at DFW (2.7% share) than DL (2.4% share).
Who knows what's going to happen to CVG. They have 80% of the market, but for how long? As elite status expires, some of those faithful who found it harder to requalify are going to drop DL and fly someone else.
DL never had more than 20% market share in DFW, which was part of the problem.. they could never crack the local market. As you well know, ORD is now the only airport that has two network carriers hubbing there.
Your statistics is unfortunately not accurate based on DOT data. IN the most recent quarter, DL carried about 12% more passengers and revenue from DFW than US.
DL is the 2nd largest airline at DFW and that will not change with the CO/UA merger based on their current shares.
What is interesting to note is that DL has passed AA as the largest network carrier at both BNA and RDU, former AA hubs. Even though those cities ended as AA hubs years ago, AA remained the largest network carrier but that changed in the past six months. Further, while AA has pulled down capacity in STL by 33% over the past year, DL has increased it by 60% even when accounting for the end of the NW operation in the past six months. DL now has about 80% of the capacity at STL that AA does. In addition, based on current schedules, DL will bypass AA as the largest network airline at BOS on both domestic and international, a title that AA has held for years.
While there have been predictions of DL's demise at CVG for years, they continue to hold onto the local market. IN fact, there are very few major markets from CVG where DL is not the largest carrier by share and even when the carrier with the hub on the other end (such as AA in DFW) is larger, the other carrier is more than 10 points larger than DL... thus no more than a 60/40 split. It is precisely because DL has maintained its lead in the local market overall and still has maintained a near equivalent share even to other carrier hubs that no network carrier is likely to take CVG from DL. When you consider that CVG is surrounded by low cost carrier operations in other cities, providing little incentive for any carrier to engage in a costly battle with DL. Even in SLC - a market that is 40% larger than CVG and which WN has had a presence for years, WN has not managed to obtain more than about 15% of the revenue.
In PIT, a market in which US walked away from key markets, US still manages to be the largest carrier with 25% of the revenue share while WN has half of that.
Unless DL walks away from the key markets in CVG, it is not likely they will lose the local revenue or that a low fare carrier will find it worth their while to try to set up an operation large enough to successfully compete with DL.
Even with DL's reduction in CVG service, they still have nonstops to the top markets and provide CVG with transoceanic service which exists in only a handful of markets in the midwest.