Basically it's inertia. How would people handle using all the existing 120V devices with 240V outlets? Most Americans don't know this, but there already are e

Basically it's inertia. How would people handle using all the existing 120V devices with 240V outlets? Most Americans don't know this, but there already are exiting NEMA 240V outlets in use in the US. There's, of course, the commonly-known "dryer outlet" and "stove outlet" (which are each unique to that application), but there's also some standardized ones for lower currents than those. Sometimes you'll see them in (older) houses that have very large window-unit air conditioners, because 120V isn't sufficient to run an A/C over a certain BTU rating. IIRC, these outlets look similar to regular 120V outlets except one of the prongs is sideways. You're absolutely right that most electronics these days can run dual-voltage; they do this because it's very easy to do with modern switching power supplies, and lets you engineer and sell one product worldwide instead of making different versions for different markets, and all you have to do is include a different power cord. However, changing the infrastructure is a totally different proposition. Lots of things don't work on 240V: think about toasters, refrigerators, lights, etc. I even have a German-made electric toothbrush which only runs on 120V (presumably, it uses a simple transformer in the charger base, which is inductively coupled to the toothbrush; the charger base is only rated for 120V, since transformers have to be tapped for the appropriate voltage). Basically, it would be cool if the entire country switched over to 240V outlets everywhere, as it would give us superior toasters, vacuum cleaners, etc., but there'd be huge confusion for a long time, probably some fires, and the benefit generally isn't worth the cost.