I'm not a finance guy but how would DL's bottom line look like if DCI disappeared? Every passenger that gets onto a DCI flight is either:
1. Flying one leg on DCI
2. Connecting to a DCI flight
3. Connecting to a DL flight.
If the mainlines are not worried about their regional feed in the next few years, they are foolish. DL seems to be the airline that is taking this seriously. What I DL doing is setting up Endeavor for a possible merger/staple down the road. Wholly owned, procedures and manuals aligning, etc. When the staffing gets critical they can flip the switch. If the entry level job at DL is an RJ FO at 70k+ a year they will have a line out the door. Pilots leave in droves from other regional carriers and the competition suffers.
I know a senior check airman.