If you're aiming for inaccuracy, that would be better.I think it would be better put that wecannot evolve anymore.
We certainly can still evolve. We don't need to evolve at the moment for reasons you mentioned in your post, but change our environment significantly, and we will evolve (or go extinct).
People tend to think of this in the short-term, but evolution takes a very, very long time. Just look at the history.