The big error he makes is that he fails to subtract the cost of the ICE drivetrain to find the incremental cost of the EV drivetrain, which is the relevant point of comparison.
This really agitates me. His assumed 40,000$ per "Electric drive system", which probably includes the battery, isn't that far off if we consider the 85 kWh version of the Model S, which will not be all of the 20,000/year production. The increase from 40 kWh to 85 kWh is 20,000$, I guess the basic battery + drive train + power electronics etc. could add up to another 20,000$ in the base model.
But the fact that this includes the entire engine and other components while what he compares it to is, well, sort of an appendix to an existing motor makes his article complete and utter bogus. Why not quote the price of a Performance Signature S? After all, the only thing I get from spending that money is fuel savings. No performance, no reduced noise pollution, no ability to plug in at home and not visit gas stations... I could rant some more, but I'd just waste my (and possibly your) time. *sigh*