How would that increase security?
"When goods do not cross borders then soldiers will."
Trade keeps people from trying to take things, and when they take them, they prefer to take them off of corpses. Isolation leads to jealousy and we're already isolated enough.
Years? No:
https://www.eia.gov/energyexplained/oil-and-petroleum-produc...
Last year, yes, for the first time since 1949. But even in 2020, we were importing more crude oil than we were exporting. The difference was due to the refined products that we exported.
https://www.eia.gov/energyexplained/nuclear/where-our-uraniu...