No, we'd be in the dark ages if we were in still the dark ages. Our current level of progress would seem like science fiction or even magic as little as a century ago.
I think I understand your point, that we have so much more to learn we're not even able to quantify what we don't know.
But this is not some kind of endless quest. We're dealing with a machine in the end with finite complexity and eventually it will be understood fundamentally.
I don't think I would be surprised if the most common diseases were eliminated in the next 100 to 200 years.