There is a fixed amount of oil in the earth. The next barrel of oil is always harder to get at than the last. The USA had a major technical revolution in getting fracking to work, and the price of oil got high enough for it to be profitable, and we did something amazing and are pumping a ton more oil than we were previously. Eventually that frackable oil will run low again too. The price of oil will go up, making perhaps new reserves proftable, maybe those won't be int he USA, or maybe solar/wind will be more attractive than oil at that point.
it is unknown! but we certainly shouldn't make long term 10-20-50 year plans on the assumption that the USA will be energy independent due to oil.