He's wrong. Spending 20k on a hybrid car facilitates demand for a hybrid car, which leads to better hybrid cars. If your buying it to directly (rather than indirectly) improve the environment, you don't get what your are doing.
That's true it's another effect, but I doubt it means hybrid cars win e.g. it seems you could have a greater impact by speeding up the development of hybrid cars just by giving the $20,000 in cash directly to Toyota.
