cubic kilometres of airspace can be locked up so as to cosset one ADF aircraft is a product of culture, not science or money
It surprised me, having done my ab initio VFR training with a US military unit where the training areas were listed as "Danger Areas", to come home to Oz where training areas were "Restricted Areas". Traffic transiting through our US training areas ranged from lighties to airline Electras, all on a see and be seen basis, no radio comms (1967).