I think Steve Jobs was sufficiently detail-oriented that he would have spent some time in their factory before investing $100M+ with them.
You have the whole situation backwards. Apple structured the negotiations and the final agreements in a way that was designed to reduce GTAT to the status of a captured supplier. Apple was also responsible for causing some 3 to 6 months of delay in the 12 month production schedule called for by the contract terms Apple dictated. Apple did so by failing to make the facility available on a timely basis and by failing to make reliable water and electrical power services available as required by the sapphire furnaces.