The context was Windows users, since that’s who Phil was talking about, and the number was 600 Million which is the number of PCs older than 5 years, which Apple hopes to attract. Why buy a new PC when you can get a 9.7" iPad Pro?

I’m pretty sure his context was over 600 million WINDOWS machines still around — at least that’s how I heard it — since he was talking about Windows users replacing their machines with iPads. If you roll back to the Keynote it’s @46:00.