What would happen if everyone owned a hybrid vehicle?

Lets say that a majority of people owned a hybrid vehicle...which is basically only produced by foreign Honda and Toyota i believe. What would this do economically? How would this effect gas prices? the environment? Would Ford and Chevy continue to produce more gas guzzlers and just reduce the prices on them? Or would they need to increase the prices on those vehicle? Or maybe just stop making guzzlers?? Maybe they would begin making more and more hybrids or some other alternative to compete with Honda and Toyota...what would be the immediate and long term impact if more and more people bought hybrids??