[elihu]

AC won out historically because it's easy to change the voltage of AC using a transformer. If we reach a point where modern DC-DC converters are cheaper or better than a traditional transformer, then I don't see why we wouldn't just use DC everywhere. (I don't know if we're actually there yet.) With DC, you can transmit more power over the same wire you'd use for AC (no skin effect), electric shock from moderate DC voltages isn't as bad as AC, and you mostly get rid of 60-hz RF noise.

One argument for AC though is that it's easier to make AC switches, since those have a self-extinguishing arc. Maybe even household light switches can be replaced by solid-state devices?

Aside from the difficulty of making reliable switches, I'm not aware of anything about DC that makes it inherently more dangerous than an equivalent AC voltage.

[ncmncm]

The physical design of the switch ought to be easy enough to make physically interrupt the arc.