Keeping the lights on is an absolutely essential societal function, and for keeping an economy running. But expanding the technological capacity of the US is what made us so much wealthier than any other country in the world. And expanding that technological capacity faster than the rest of the world comes from attracting the best technological innovators from the rest of the world. However, with China's and India's size, it's likely that they will now be able to overtake us without relying on much immigration.