Mention of Launch Escape System (LES) brings to mind images of the crew on board a spacecraft ejecting at launch; the crew being the most valuable cargo on board.
Launch vehicles may also be unmanned, e.g. PSLV/GSLV, Ariane, etc. In this case, the most valuable cargo on board is probably the satellite(s) it carries to orbit.
Was a case ever made to preserve the pay-load on board in the event of a failed launch by means analogous to LES?
Why don't unmanned launch vehicles at present include LES for their pay-load?