It's not so bad an article, even with mistakes. I haven't seen such a nice summary of the various alternatives being considered before, and the plot of energy density targets seems very useful as a compact reference. I know more than I did before reading it, even if some of what I now "know" may be in error...
It really does blow the discussion of energy density. First, the Model S 85 battery holds the equivalent of 2.5 gal / 9.6 L of gasoline, not 7 L. Perhaps they used some measure of "useful capacity", but I've never heard a gas tank characterized by the amount by which its volume exceeds the reserve tank.
Second, as techmaven points out, the entire point of EVs is to do the range on much less energy and no emissions. Which would we prefer? 2.5 gal tanks that go 250 miles, or 15 gal tanks that go 250 miles? If we had Tesla sized batteries with the same energy density as fuel, we'd have ranges up towards 2500 miles, which is not a very practical goal since no human could possibly drive anywhere near that far without a break. Not to mention that charging time would become that much more challenging as well.
I personally would applaud ranges up to 500 miles / 800 km, and it sounds like they may be within reach before too long. Then if the charging time on the highway can be kept down to the time it takes for a snack and a bio break (30 min), it seems to me that one would reach the point of diminishing returns for further investment in battery tech, either at the R&D or consumer levels.
There was no huge investment in gasoline tank capacity or pumping rates. It was inherently cheap, potent and easy to transfer. But that will be less true as it becomes more scarce and expensive, and as the other costs of using it accrue and are appreciated.