I think this is exactly what is happening. Airways/United was blocked once already due to east coast monopoly (right?) so why would they be allowed now. Continental and United has been setting up for a merger for a long time; common reservation systems, shared/close gate areas, alliance.

COA has been wary of merging and now United is setting up for a forced merger. Either CO and UA merge or conti is Left out in the cold on their own.