The author seems to subtly misunderstand the main reason that the Volt is only a concept car: the politics of minerals.
Battery packs like the Volt's aren't too expensive for a few hobbyists to retrofit into their Priuses. But lithium-ion batteries (as opposed to the NiMH chemistry in factory hybrids) require the element cobalt. A large production run of cars with such batteries would cause a global shortage of this element.
This wouldn't matter much, except that cobalt is also a necessary component of the superalloys in turbine engines for airplanes and tanks: a run on the market would force all major military powers into a buying frenzy, in the name of national security. Ironically, including a turbine engine in the car would only make the problem that much worse.
The only hope for affordable lithium-ion batteries in sufficient quantities, barring pie-in-the-sky plans to mine asteroids, is to do without the cobalt.
Some experimental cobalt-free Li-ion chemistries have shown some promise. Not only would they make plug-in hybrids more feasable, they would reduce the ecological damage from toxic cobalt waste. One of the most mature alternatives is a manganese-based material used in pacemaker batteries, where cobalt poisoning would otherwise be a concern.
I agree with the article's general tone, though, that a more-radical re-thinking might be necessary. My personal favorite is a brayton cycle engine (maybe turbine, but hopefully a positive-displacement design) with a (relatively omnivorous) solid-oxide fuel cell as the combustion chamber.
Keep up the good work,
Joel Hollingsworth
former undergrad researcher on alternative Li-ion chemistries