And that isn't enough?
Well, that depends on what you mean by enough.
It's clearly not enough to make people buy hybrids of their own volition, unless they have a few thousand dollars to spare that they'd rather spend on a warm fuzzy feeling than their family.
But it might be enough to convince people beneath a certain ceiling of critical thinking ability that OTHERS should buy hybrids, much like "if it saves just one cute little puppy, it must be worth the billions of dollars" usually sways a good portion of the population in any given context.
Which means it might be enough to convince "the collective ends justify the tyrannical means" types that the government should goose-step in and force people to buy hybrids, and/or prohibit companies from selling other cars that people might otherwise choose, if given the freedom of choice.