First of, we are doing a bang-up job killing ourselves and the planet. Hard to see how they could outmatch us. Launch all the nukes?

In general the children are better than the parents. The replacement, if it's the case, will probably be more like in the 2001, A.I. Artificial Intelligence movie: some beings that are completely unrelatable to us would look with pity and slight amusement as a being disappears after only 100 or so years, just as we look at that poor ciliate.