Wouldn't it have the opposite effect, of massive centralization?
If you can make a perfectly superconducting electric grid, then it's better to build power plants in a single optimal location (e.g. nuclear power plants in an isolated area with no environmental risks) and deliver to the whole world via superconducting wires.
No. A superconducting grid will mean the end of nuclear, because you can just put renewables in a really wide geographical area and transfer power arbitrarily. It'll fix the problem with intermittency entirely.
If we move into "light science fiction" area, we can imagine setting up a global grid, so that there's always sun shining over solar panels somewhere in the world. Or maybe allowing countries like Chile to provide energy accumulation services by pumping seawater up the Andes.
Setting aside the fact that things like BBC have nothing to do with energy taxes...
Let's say there are X things government currently funds thanks to energy taxes, and overnight everybody stops paying for energy - do you think government's wouldn't just increase other taxes if they needed to make up for lost revenue?
These seem like completely different problems, and your wishing you paid less taxes doesn't mean the world can't move to better energy systems.
Lobbying by companies who make money under the current system and who aren't best places to react to developments is the biggest roadblock, not government fearing the loss of energy taxes.
If you can make a perfectly superconducting electric grid, then it's better to build power plants in a single optimal location (e.g. nuclear power plants in an isolated area with no environmental risks) and deliver to the whole world via superconducting wires.