If the conditions are optimal for the form they are in then they will exist in that form. Sharks are older than dinosaurs. They likely will not change since they don't have to.
When an evolutionary step occurs the new version replaces the old version. There were many types of proto human but we are the only version left. We ate the other ones.
In short: they already became human over the past billion (?) years. It's not going to happen the same way again.
