Kiper used to be a draft expert, but now he has a team of people who do everything for him.
IMO, his process is as follows:
Put out a mock.
Get feedback from a few NFL contracts that he has.
Update mock based on feedback.
Put out updated mock.
Repeat
Repeat
Repeat
Nowhere in the process is Kiper actually watching game footage involved.
In the past I thought he had great recall because on TV they would ask him about some 7th round type player and he could spew out an analysis of that player. I later figured out that they cued him ahead of time on the question.l