Suppressing? That's a laugh. As Ardius says, manufacturers are spending boatloads on alternative technologies. GM built the electric car. They leased it at a loss. And yet, they didn't get enough business from it to even begin to justify the huge financial loss from a marketing standpoint.
Toyota sold Prii at a loss for years, before they finally amassed enough sales to break even. And even then, it took a large government subsidy on both sides of the Pacific to make it work.
Manufacturers continue to squander billions on hydrogen development. Know why we don't have hydrogen cars? Fuel cells cost too damn much.
Manufacturers already sell natural gas and propane automobiles. Consumer interest isn't nearly enough for them to justify making more of them. Heck, I'm a propane user and even with my grassroots enthusiasm, I can't honestly say it'll work for everyone.
I've also dabbled with electric cars enough to know that an electric available for the same price as an economy gasoline car will not have the same features as one. Want something for Honda Fit prices? You'll have to settle for something with the build quality of a 90's Daewoo and electrics worse than Lucas.
All the major manufacturers know that the first one to stumble upon the next big thing will make gigabucks in profit. They spend billions chasing down thousands of different methods for creating greater fuel efficiency or avoiding petroleum altogether... And yet, unless the public is willing to pay the price for these "alternatives", they're never going to become the norm.
