The US has _always_ been the first or second largest crude oil producer since the beginning. Not much has changed. We just have millions of oil wells, whereas Saudi has only a few hundred, many of which had naturally pressureized well heads (no pumping required). In fact the largest single oil well on the planet is in Saudi (it's called Ghawar https://en.wikipedia.org/wiki/Ghawar_Field, which is such a lovely name) and it's over 150 miles long!