Wall warts can use small windings because they limit the energy supplied to the transformer. "Switch-Mode Power Supply"
The better solution from a "limit the losses in event of failure" point of view, for power transmission, is to do less of it. Generate power local to the points of consumption.
That is the ultimate solution.
No centralized grid, no centralized vulnerability.
Something that causes every big government/central planner screaming nightmares. A structure they can't shut down or throttle by fiat.