Well it all comes down to the same basic thing. Money. The government does not want to stop getting oil. They are not interested in developing hybrid vehicles or anything that will cause consumers to stop buying gasoline. For every gallon of gas you pump into your car, the government gets tax money, they get sales taxes, they get income taxes from the oil companies making profits, they get kickbacks from the oil companies for limiting production of anything that might pull away from people buying gas.
To put some numbers to this, lets look at it like this. Lets say 100 million vehicles in the United States (to make the math easy). Every vehicle gets 5 less gallons of gas per week. 5*100,000,000=500,000,000 gallons of gas @$2.25 per gallon (current price here in California)=$1,125,000,000 per week that the gas/oil companies dont make.
So, who cares about a few dead animals and plants? Who cares about a measley few hundred million dollars spent to build and maintain the drilling system? They have to keep that gasoline flowing, thats just too good of a source of income to allow to slip away.
Steve