I have a PhD in Cognitive Science (from Carnegie Mellon, 1996). I've gone back and forth from industry jobs and academic jobs. When you are at the post-graduate level, being able to publish and share your ideas is a major thing. If I was looking at jobs, and I was told at Apple that I would not be able to publish, that would put a big damper on my enthusiasm for working there. I realize I probably won't be there for my entire career, and so you have to think about what comes next. If you have a 4-year gap (i.e., your tenure at Apple) on your resume where you cannot point to papers you wrote and the conferences you attended, your ability to transition from Apple to your next gig will be severely hampered. The top people coming out of the top AI places may not consider Apple for that reason.