Outside of the internet / IT sector that is.... Some people I follow, like Mr. Pinchbeck suggest that agriculture, water reclamation, energy (including renewables), and health are the areas where Americans can still innovate and pioneer new ground.
These things allow us to imaging a few possibilities for working towards a more sustainable future, if that is something you choose to do. These things can be approached from a for profit, close source, open source, not for profit etc.