Not every period of evolution in a taxonomic branch is going to involve adaptive radiations. Although early human evolution is generally thought to have involved an adaptive radiation, by the time we get to 2mya a lot of the literature was assuming only 2-4 species existed over the next 2 million years.
Teleology was used somewhat tongue-in-cheek. The older literature was problematic because it aligned too neatly with anthropocentric ideas of goal-oriented evolution, and gave rise to nonsense objections like "Where is the missing link?" and "Why are apes still around?"
I don't doubt the integrity of the scientists who were involved with the earlier literature, but in hindsight it looks an awful lot like a teleological bias.
Not every period of evolution in a taxonomic branch is going to involve adaptive radiations. Although early human evolution is generally thought to have involved an adaptive radiation, by the time we get to 2mya a lot of the literature was assuming only 2-4 species existed over the next 2 million years.