Well now that the sentence has been revised, it makes sense. Because of advents like modern medicine, humans can now survive things which would have killed us in the past, and so natural selection doesn't act very strongly on humans anymore. That's not to say that we aren't evolving, just that we are evolving slowly. However, Eliot, there is no top of the evolutionary ladder. There is a common misconception that humans are the pinnacle of biological adaptation. However, all species are equally well adapted to their own niches. Humans are at the top of the food chain though.

Your sentence is wrong. Rewrite it correctly, then we can help you.

Well now it sounds just right. get stuck = get stuck I think you know what it means. Technically, humans are at the top of the evolutionary ladder (most of us are, anyway). Some guy is complaining we're not making any progress, so we are stuck. That is what he means.