[highcountess]

To answer your question, it already has changed us in many ways. You are not the only one who does not realize this though. It is in fact the prevailing position.

We have diseases and genetic defects, among other impacts through modern behaviors and environments/toxins, which are also retained in the genetic mutational load. We even have a whole lot of energy and human activity working to counter evolutionary pressures and assure those accumulated mutational loads remain in the genetic code.

[amanaplanacanal]

Fitness depends on the specific environment the creature is in. Environmental fitness for the ancestral environment when all humans were hunter-gatherers is not necessarily the same as fitness for living in an industrial society. Evolutionary pressure still works just fine.