Has medicine killed us?

We've (been provided with/evolved) a very smart and effective immune system. It fights or at least tries to fight everything which could be bad for the body. It has carried our bodies through plagues, epidemics, diseases etc. through all this time of human existence. However, very recently we humans have discovered medicine technology which mostly uses chemicals to fight all things bad for the human body.

It's all good. However, there maybe a catch. The natural immune system uses organic bodies to fight harmful bacteria, and unlike chemicals both these organisms are always mutating, based on the kind of challenges put to them. They evolve at more of less the same rate and the evidence of this fact is simply the existence of each species, otherwise one of them would be extinct by now. But these organisms evolve only when put to test against it's enemy, which has largely been avoided for our immune system through the advent of modern medicine.

The result of relaxing our immunity and putting ever-increasing resistance against harmful organisms has lead to slowdown in growth of human immunity and an rapid empowering of bad-bacteria.

I think we humans need to have a little more foresight in terms of technology and where it's taking us. It's okay to save a few lives quickly but not at the expense of threatening humanity's existence.

Ever heard a marine-life researcher say that dolphins may be smarter than humans? Well, one argument against that has been the seeming primitiveness of these sea mammals. To that what I have to ask is, what makes us think we are so better off? Are tools and technology the only measures of advancement in civilization? Couldn't a well-evolved brain or a highly effective immune system or communication-without-wires-and-radio be considered a sign of superior technology? Maybe that's where we are headed with discoveries in genetics. And who knows, after we find out enough, that we realize, we're not as special as we think.