Laptops on Airliners

Atlantic magazine has an article about the difficulty of providing 120 volt AC power at each seat to charge passenger laptops. Clearly the Atlantic people are journalism majors who have trouble changing lightbulbs. (How many J school students does it take to change a light bulb? Five, one to hold the bulb and four to rotate the stepladder.)
Allow 100 watts per laptop charger on a 200 seat aircraft and you have 20,000 watts, about what five electric kitchen ranges take. It's a respectable amount of power but nothing that the jet engines cannot provide. The engine drives an AC alternator thru a power takeoff shaft. In fact airliners since the DC-6 (and maybe earlier) have 115 volt AC alternators, one on each engine. There is plenty of power available to drive the alternator. A 20 Kilowatt alternator only needs 26 horsepower to turn it and jet engines furnish thousands of horsepower.
In fact, it's only a matter of wiring up each seat. All jetliners currently generate 120 Volt AC power at 400 cycles per second (hertz). 60 cycle electrical equipment works just fine on 400 cycle power. We used to operate delicate electronic test equipment out on the flight line off 400 cycle power. Worked fine and lasts a long time.
So, all that is required to bring laptop charging outlets to all the passengers in coach is will on the part of the airlines. Doing it right would be to have Boeing and Airbus do an engineering change order (ECO) to fit a passenger charger alternator into a couple of engine nacelles and do a cabin wiring diagram. An ECO of this nature would have to be reviewed by FAA for safety and and that takes time, but it's doable. Installation would take the plane out of revenue service for three or four days. Not cheap.
Cheaper for a small outfit like Virgin Atlantic, would be to just wire the cabin, and either install an inverter to convert aircraft power to 60 cycle AC or just run 400 cycle aircraft power to the seats. Cabin wiring can be customized by each airline and changes, like laptop charger circuits, probably do not require FAA approval. That's the low cost way to go.
As soon as one airline decides that offering laptop charger plugs will bring in business, they will put 'em in. As long as the airlines think the passengers don't care all that much, they won't. It's a matter of economics, not technology.