Surely, 7 million years estimation has big uncertainty, and it could be shorter, but unlikely shorter than 1 million year, as chimps have to undergo important anatomic changes to become human-like: they need to have larger heads, different walking and hanging anatomy, different voice anatomy etc, and selection for such anatomic changes was slow in humans. Also, most catastrophes which will kill humans will probably kill chimps too, as they are already endangered species in many locations, and orangutangs are on the brink of extinction in natural habitats.
However, there is another option for the quick evolution of intelligence after humans, that is domesticated animals, firstly dogs. They have been selected for many human-like traits, including understanding voice commands.
Chimps in zoos also were trained to speak some rudimentary forms of gesture language and trained their children to do so. If they preserve these skills, they could evolve much quicker.
Surely, 7 million years estimation has big uncertainty, and it could be shorter, but unlikely shorter than 1 million year, as chimps have to undergo important anatomic changes to become human-like: they need to have larger heads, different walking and hanging anatomy, different voice anatomy etc, and selection for such anatomic changes was slow in humans. Also, most catastrophes which will kill humans will probably kill chimps too, as they are already endangered species in many locations, and orangutangs are on the brink of extinction in natural habitats.
However, there is another option for the quick evolution of intelligence after humans, that is domesticated animals, firstly dogs. They have been selected for many human-like traits, including understanding voice commands.
Chimps in zoos also were trained to speak some rudimentary forms of gesture language and trained their children to do so. If they preserve these skills, they could evolve much quicker.