Who dictates Nikon release schedule – engineering or marketing?

Since I have no interesting rumors to report, I decided to share one of the emails I received recently – there is no way to confirm if this is all true: I was told that Nikon is already working on their 2012-2016 product line. The technology is already here and new product are fully developed and ready to be released – the actual announcement schedule is decided by the marketing department. Nikon usually is sending early samples to photographers to test 1 or 2 years before launching the product on the market (of course, under NDA). It seems also that Nikon and Canon agree on some product releases as well (timing, features, etc) – I have read this before, but could not find any references online.