It would be useful to check your facts before disparaging informed opinion. What was true a century ago has not been true for at least a half century when DC voltage conversions become practical. Also, in that time the use of solid state electronics has become a dominant use of electrical power. 
Solid state devices like LEDs, computer, cell phones must ultimately use low voltage DC. We could gain system efficiency if we eliminate all the conversions from high voltage AC to DC. LED lights would be cheaper if they did not need to be used in AC circuits, for example, as are all the things that need wall warts.
The longest high voltage transmissions are DC because it is more efficient. DC has less loss underground and underwater because there is little capacitive or inductive loss. DC connections do not need to be synced so the Eastern grid is connected to the Western grid through DC.
There is another relatively recent inventions you should learn to use(e.g. Google).