I wouldn't dismiss Kooij to Astana just yet, they already signed his leadout man and seem to have a capable sprint train.In the case of Bennett and Welsford yes. The brought Meeus instead who won in Paris. So that was a level descision. Ackermann...they threw him out because of Sagan in the end as well as wanting to go for a GC Top 5... both were factors imo.
With Kooij it would be different but on the other hand Denk wants to win the Tour and I see them betting everything on Roglic even though he can't win in 26.