From what I've seen, he seemed to have a knack to attract top talent and push them to their limit.

He was able to charm those people he needed and knew just how to push their buttons so they'd deliver better work.

Contrary to what people thinks, assholes are not assholes 100% of the time; those people get their way by knowing when to be nice and charming. This is not antonymic with being an narcissistic asshole.

I'm fairly sure a lot of his collaborators had a honeymoon period with him, before he revealed himself to be the management equivalent of the abusive husband.