From CNN.com: America's untapped oil

Oil companies and many lawmakers are pressing to open up more U.S. land for drilling. But the industry is drilling on just a fraction of offshore areas it already has access to.

But why would oil companies not drill in these areas?  Here's an answer:

But fearing oil prices will eventually fall, the industry is leery about making too many investments in the fields it has - many of which are in deepwater areas that can be pricey to develop.

Instead, they're holding out, hoping the government will open areas closer to shore that would be cheaper to work on.

The Oil Companies are waiting for something much more profitable to be handed to them by the government.