It might lead to increased volume down the road. But if it was about increasng volume they would still have the routes running on Monday. I clearly have a clue I have Sat and listen to conference calls about it... Stop assuming things that you haven't personally heard about from a DM or above...
Do those calls last longer when they have to stop every few minutes to explain everything to you?
Someone earlier compared the rollout of Saturday ground to the start of Next Day Air. This was volume that we never had and it took a while to educate the public. Although it has been on the decline domestically due to cost and other factors, NDA is still a significant revenue source.
Saturday ground will start by cannibalizing Monday volume, which will result in numerous routes being cut and areas combined, until such time that the volume has increased to the point where it will become just another delivery day. This will not happen overnight.
The cars will be loaded per Monday's plan and work will be moved around before start time on Monday to balance the dispatch.