Re: No they don't
The reason we use AC is that voltage transformation is easier, so the changes needed to get from power stations to homes is easier. For long distance efficient transport of power we use DC in the form of HVDC. This is 80kV or more (800kV in china). These converters are expensive, so only used when the power transfer justifies it or where AC just doesn't work (e.g. underground cables more than 100km long).
AC is good for spinny things too. Not everyone has nice variable reluctance motors in their appliances (thanks F&P), so single phase induction motors are going to be around for some time.
A standard home DC bus of 48V or so would be nice. ELV, so no licence required for DIY work here in Australia at least.