Barkley, you have given us no idea what idea it is you say is so important.

Is your claim that what it means is that there are some times when evolution of bony parts is fast, and other times when it is slow? That follows directly from "adaptive radiation", which has been known for a very long time and which suggests a reason. Nothing new there.

If it's such an important idea surely you can tell us what it means. Take all the time you want. Don't worry about it scrolling off, we'll wait for you.

At this point the argument isn't whether PE is important. The question is whether you know what it says. We can talk about how important it is after you show us you know what it means.