I sure do fucking wish it were that simple, and possible everywhere. But it isn't, in places like Australia, Brazil, Russia and South Africa, you can't just grow enough food exactly where it is consumed, because people live elsewhere and the food needs to transported vast distances, and in many cases the capital input to get something is too damned high for anything but the largest and most massive megafarms.
Its only the rice munching cultures of East Asia, and parts of Europe and North America, where farming even could be de-corporatized and still attempt to feed everyone
What the fuck?! Thats not how any of this works, at all. Every major city outside of large garrisons of the former Russian Empire became major cities because of commercial advantage, and almost always because of access to water transport, whether that be oceanic or riverine, usually both. The large cities would see another explosion of population
Yeah sure, after they finish slaughtering each other
No, I won't humor you on this you fucking retard
This is almost acceptable. Except that improved Lithium batteries are on the horizon, and current Lithium batteries are already incredibly fucking good. On high end phones, turning your power mode to ultra savings and not dicking off results in a battery that last for 10 fucking days if you don't touch it.
Hand cranked rechargers already exist, as do small portable solar panels that would be good enough
If the resources exist for black powder to still be a thing, then smokeless powder would also exist. As would Cordite.
The absolute fucking worst that would occur is a knock back to ww1 level of chemical engineering for gunpowder, which means Direct Impingement gets a hardy fucking NOPE, and everyone is using Long Stroke Piston rifle designs.
Early 20th century chemistry is simple to what we use now, if less consistent and dirty burning. But if the minerals exist for black powder, then we won't be knocked back that far. Too much knowldge has proliferated too far.
As far as energy goes, you stupid Australian, your country could have plentiful renewable energy within 5 years if your politicians were worth a fuck, you would only need to pay for maintenance, LIKE ANY OTHER FUCKING POWERPLANTS