Hi
This is a quick note. This is very interesting. First, nobody can predict what may happen so if a comments collides with earth then we are all gone. Something more exotic may occur as well like a supernova in a nearby star or other phenomena.
However, aside from that, there are a couple of forces at play here. Some claim that ideas/concepts also evolve much like species so there is a parallel evolution in the realm ideas/culture/society.
Technology could also out pace human evolution. Look at the pace the chips improve (moore's law/statement). There might be a danger there if artificial intelligence actually out paces human intelligence. Microchip technology, nanotech, and bio combined could produce AI in the near future.
Wouldn't it be important for the human race to try and evolve even further. By perhaps an artificial man made evolution?
Regarding the argument of devolution (backwards evolution) with the example of glasses and certain people that would not survive if it weren't for modern technology, my argument is not humanitarian but again based on evolution. Basically indeed certain people survive due to modern technologies nowadays however you got to remember that a) humans create a society in which they need to survive b) so if the fittest survive in the society c) and if the society does not have as a prerequisite for survival physical attributes e) but mental or intellectual attributes f) then a person wearing glasses or having some disability g) if intellectually capable would survive, Then what about the mentally handicapped? That is a good question. But although I may be perceived as cruel I do not think people with mental problems such as mongoloids should be allowed to procreate. It is not fair to society and their offsprings.
Government control of evolution is very controversial, but has occurred. Hitler's misuse of this has given it a bad image. But in my country, Sweden, the government did sterilize mentally "unfit" people earlier, this stopped in 1976, and is now regarded as very unacceptable.