Why aren't these technologies more commonplace now?

Because, while the technologies exist, the corporate and political will to put them into widespread use does not. Many companies in the automobile and energy industries put pressure on the White House and Congress to halt or delay new laws or regulations -- or even to stop enforcing existing rules -- that would drive such changes. From requiring catalytic converters to improving gas mileage, car companies have fought even the smallest measure to protect public health and the environment. If progress is to be made, the American people will have to demand it.