Although I understand the focus on 'higher taxa' as 'monophyletic clades' in the more recent papers on this topic, I somewhat befuddled by the lack of reference to the paleontological literature on this same topic (e.g. Patzkowsky, 1994; Foote, 2011), which allows for paraphyletic 'para-clades'.
At least in my own experience, the fossil record often shows nested paraphyletic groups replacing one another (in terms of richness), due to factors such as extinction events or key adaptations. For example, this is very common in the graptolites (my group) but many others also. Thus, I think if we really want to talk about the evolutionary dynamics of 'higher taxa' we should be discussing the dynamics of paraphyletic groups.
Do we really think the higher taxa in the (extant) groups we study are defined based on some relationship of the age of monophyletic clade or, conversely, are groups defined by morphological distinctiveness and richness, often with an untested potential for monophyly? Me, well, I don't study extant things so I can't answer that.