In my book, "Oblivion" was a stinker, the biggest plot hole being an intelligent machine[supposedly] needing energy
would have done better to just park itself near the sun, or any sun. Or if fusion fuel was needed in a cooler form, then the outer solar
system, with the gas giants Jupiter and Saturn would have been better choices, plenty of hydrogen and helium, with their moons, even
Neptune and Uranus, some of it in frozen form. Thusly compacted, gobs of methane [natural gas ] as well,also frozen. Far more than the waters of Earth could hold.
Plus it takes energy to separate water into hydrogen and oxygen, yet only a spark of lightning for the reverse in taking oxygen and hydrogen to make water.
Though it was a visual delight, After Earth was the better movie of the two, though evolution doesn't occur that quickly, it would have taken hundreds of years for grass and plants
to reclaim the land followed by animal species filling in the niches vacated by man. The Smiths' should have written a longer time line.