I take your point Melchett, but the politicians decide how much they are prepared to pay for the insurance policy. When crises occur, then will then call the insurance company (the Military) and ask what can be done. Based on their premiums, the insurance company will explain the possible options from which the politicians choose.
You might think they will regret this in future, but the fact is that at the moment, the politicians are not prepared to pay more for their insurance policy.
Whether one likes it or not, our innate ability to deploy operational capability IS determined by the spreadsheet. It is naive to think otherwise.
BTW, a trip overseas that can "ensure that the same numbers of people and aircraft/ships/tanks come home as deploy" is called a Holiday, it's certainly not called an Operation.