What is epically idiotic, is that the 757's were flying FULL and generating tons of revenue, irrespective of their costs or efficiency. Look at the UA financial stats two years prior to the merger.
They could be used on all the city pairs which require the thrust and the brakes which only that plane has. The shiny new guppies could be used for expansion or reclamation of routes now being sullied by the GD RJs. We could be growing and competing with DAL.