> We have not ended up with "humans which aren't as strong, aren't as smart, aren't as well adapted to a changing environment, etc."
Haven't we?
This line of reasoning leads to “some people are weak and unworthy of life because they are impure.” I don’t think rolling back our work to end infant mortality to prevent weak people from living is the right answer.
Objectively we’ve only become smarter (IQs have increased), stronger (fitness records continue to be broken), etc. since infant mortality shrank. If you believe otherwise please provide evidence.