[Rduke55]

This is a topic that always sticks in my craw. People make it out to be that there's no way to separate these groups into any legitimate categories and that just isn't true with the overwhelming majority of animals (ring-species aside).

Of course species breaks are impossible to locate if you go over the entire time. You're right that the point is that with all the die-off there are reproductively isolated groups in existence that have different selection pressures and evolutionary histories because of that isolation.
Without considering these groups different species we wouldn't have near the understanding of evolution we do.