One aspect I haven't seen mentioned in other comments is that secrecy and control is part of the core Apple culture, in a positive way. Out of all the big tech

One aspect I haven't seen mentioned in other comments is that secrecy and control is part of the core Apple culture, in a positive way. Out of all the big tech co's, Apple has the strongest brand and marketing. They have built an image on good design and high quality products (this is the perception, even if you dispute the reality). They have carefully built this image over the years by releasing products very deliberately, not focused on the tech or specs inside but instead focused on the product as a whole. Controlling the narrative _requires_ secrecy during development. Every person who joins Apple today is well aware of the culture and how it has contributed to Apple's success. They have every incentive to maintain that secretive culture to continue the success.