But the inverse also applies - there’s not much stopping wizards from portkeying/apparating into the Oval Office or the pentagon and magibombing them, or Avada-ing key targets. Wizards are probably the worst kind of guerrilla fighters - ones unchecked by range. And as far as food is concerned, food multiplication is a thing. I personally believe that in the long term, the way muggles would win would be through subverting wizards, not by pure overwhelming force.