"As long as the supermarket shelves are full of food we will survive
If supply chain is disrupted for an extended period of time there would be mass panic
People would starve"
oh dear --------- you are correct - but, the disruption to the supply chain that keeps supermarket shelves full can be rapid -- instant even and those shelves could and would be empty within hours
such is the precariousness of the modern way of life if certain events occur