I think this argument is more true for personal vehicles that sit idle for 99% of the time -- they don't consume gas when they don't move.
For commercial vehicle that spend most of their life on the road, energy savings from running a more efficient vehicle recoup the energy used in making that vehicle pretty quickly.
For commercial vehicle that spend most of their life on the road, energy savings from running a more efficient vehicle recoup the energy used in making that vehicle pretty quickly.