Are they still making the EF L Lenses?
I do not know about everyone else, but in my kit the camera is only 20% of the cost. There is more involved in this debate than just the body.
I think you will see the 1DXIII in production / sold for a long time. If they discontinue the body the lenses have to go at the same time.
It would make sense they would try and balance the supply chain so they all run out about the same time.