When life gives you lemons, make orange juice and then kneecap life while it’s distracted trying to figure out how the hell you did it

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.

But they were able to setup the core of their commercial and governance infrastructure in the middle of London, with no particular notice from muggles - not to mention, we know that the government already knows about wizards (MoM liaises with the PM). So there must be a quid pro quo already in place, with the government tolerating and aiding in the existence of a semi-independent polity in their heartlands in return for unspecified benefits, probably defence against foreign wizards.

True enough, the capabilities of Magic haven’t been explored enough canonically to disprove that - but if the government learned of Magic, the first thing they’d do is subvert some wizards to their side, who might be able to counteract them - in many ways, it’s a battle of statecraft as it is of actual power.

I personally think it depends on exactly what the limits of Magic are - it could be anything from Muggles eradicating Wizards, to the opposite, all very plausibly. To me, it comes down to the power of modern surveillance vs. the power of notice-me-not + space-expansion + anti-detection spells. Plus there’s a whole bunch of other powerful spells and devices (time turners, for example), but the muggles have a while fuckton of gold and other valuables to recruit these capabilities to their side as well.

Honestly? A major breakthrough in fusion, or to a lesser extent, any other clean energy. We’ve decarbonised a decent chunk of the world’s energy profile, but there’s a strong financial incentive that politicians are vulnerable to protecting oil and gas, slowing down further decarbonisation. Batteries and supercapacitors also could do the trick.