Actually .... modern batteries really do provide enough power. The smaller, and usually cheapo power tools are still being powered by old-type Nickel-Cadmium cells. Pretty good, but soon run out of power.
Next time you pass a scaffolding rig around a building, don't be alarmed by the fact that it was all put together with a cordless 18volt Lithium-Ion drill.
Steel-framed buildings are the same. No spanners, just cordless with a socket on the end.