The argument is that oil via combustion engine vehicles compete against renewables/gas/hydro/nuclear via battery-powered electric vehicles in a single transportation energy economy.
But gas vehicles remain very competitive against electric vehicles on total cost of ownership, even with oil prices far higher than $20/barrel. And since gas is so much easier to transport, gas vehicles have numerous technical advantages.
If electric vehicles do not fully displace gas vehicles, then this article is wrong. Oil prices can stay high.
If electric vehicles do fully displace gas vehicles, the article is still wrong, because oil will not be competitive with grid energy even at $20/barrel.
Typically one needs to drive to a gas station to refuel a gas vehicle, whereas an electric vehicle can be recharged at any mains power outlet.