Given that his departure was marked by Apple products getting more reliable and usable, they arguably did too much in that regard (one of Cook’s more notable bad calls). Once he stopped blocking it, the keyboards were fixed and pro devices regained enough ports for pro users.
Without his support, his protege Alan Dye left for Meta and improved the design skills at both companies.
He "took" several Apple employees with him when he left and there's been a steady stream of Apple employees going to OpenAI.
Ive isn’t responsible for all of them obviously, but the articles about lawsuits says there are 400 former Apple employees at OpenAI.