Because when you fail a pilot it throws the customer's crew roster into disarray, and they don't see any value in a $25K course if the pilot scores a fail at the end of it. They just want the certificate, put a tick in the box, sign their logbook and be done with it. They will go to the training organization that makes that easiest for them. I've even seen company training managers skip observing sim sessions with their pilots because they were more interested in chasing the local floosies. That is the reality of the business, unfortunately.