Will Supply and Demand catch up to alternative fuels?

Can alternative fuels, such as ethanol or biodiesel, end the world's oil dependency?

It seems to me that supply and demand will always catch up to most fuels. Once petroleum was extremely cheap, so cheap that alternative fuels just didn't offer a viable enough economic case compared to gasoline.

While I'm not opposed to alternative fuels, technologies, such as hybrid cars, demonstrate that fuel is becoming less and less important. Lithium-ion powered hybrid cars with plug-in technology, for example, could take the far majority of Americans to work and home every day without any fuel. Now it is true that some electricity would be required to power these hybrids and that electricity might not come from clean sources. Nonetheless, how much quicker would a solar powered roof become cost effective if you could not only power your home, but all of your daily driving needs?