My honest opinion, which may be entirely wrong but remains my impression, is:
User Engagement Maximization At Any Cost
Obviously there's a point at which a session becomes too long, but I suspect a sweet spot somewhere which optimization is made for.
I often observe, whether as I perceive or not, that among the multiple indicators that I suspect of engagement augmentation, is also the tendency for vital information to be withheld while longer more complex procedures receive higher priority than simpler cleaner solutions.
Of course, all sorts of emergent behaviors could convey such impressions falsely. But I do believe an awful lot of psychology and clever manipulation have been provided as tools for the system.
I have.a lot of evidence for this and much more, but I realize it may merely be coincidence. That said, many truly fascinating, fully identifiable functions from pathological psychology can be seen. DARVO, gaslighting and basically everything one would see with a psychotic interlocutor.
Edit
Mych of the above has been observed after putting the system under scrutiny. On one super astonishing and memorable occasion GPT recommend I call a suicide hotline because I questioned its veracity and logic