Tobias,
You are looking at the final step of Arahanthood.
To get there, one has to proceed step-by-step.
– For example, a Sotapanna is still bound to this world. He has salayatana, bhava, jati.
– But his salayatana, bhava, and jati will not “go below” those corresponding to the human bhava.
With each higher level of magga phala, more bonds are broken.
– But until reaching the Arahanthood, some bonds remain and the corresponding salayatana, bhava, jati, etc will remain.