The only problem is people need cobalt in their daily likes as much as high speed data switching equipment.
As long as aircraft crashes on land, NTSB reconstructed all the structural elements that contain cobalt alloy steel. At the end of investigation, I assume there is some recycling company that melts it down. Consumption of cobalt IMO would require actively growing economy with more planes in air acting as valuable reservior for colbat not planes in mothballs depressing future consumption.