Just because a hub/pilot base shrinks doesn't mean its going away. Moving the sims was a separate decision altogether. NATCO was nice but the economics of having it all in one place makes sense. Even MEM and CVG have a bigger presence/route map than any other airline would provide if DL "pulled out".

IMO DL is in a good position at both markets; big enough to offer a footprint that dominates the market and business travelers and still be able to severely punish anyone that tries to poach, yet small enough to not have to run much of an arbitrary hub with needless overlap.

MEM, CVG and MSP are all good markets and I think DL will try hard to continue being the major/dominant player at all 3. The biggest threat IMO to all 3 remaining hubs and pilot bases (in 2 of the 3 cases) will be keeping the airport boards from selling their souls for the mythological "LCC effect" and trying to get DL and the local tax base to subsidize cut throat competition that will result in far smaller route maps that will hurt everyone.