Why no inclusion of anusaya/ asava in dependent origination?

Is there a compelling reason, those that draw diagrams for visualization of pratityasamutpada (dependent origination), don't want to include anusaya/asava, obviously not to misrepresent Dhamma? Because from my search, only MN9 details these hidden layers of anusaya/asava as conditioning ignorance, vice-versa? > Ignorance originates from defilement. Ignorance ceases when defilement > ceases. The practice that leads to the cessation of ignorance is > simply this noble eightfold path …” > Defilement originates from ignorance. Defilement ceases when ignorance > ceases. The practice that leads to the cessation of defilement is > simply this noble eightfold path,