It's because iSuppli study absolutely doesn't say they'll reach 10 TB by 2016, but that 60 TB on a 3.5" is the absolute maximum attainable through the HAMR tech

It's because iSuppli study absolutely doesn't say they'll reach 10 TB by 2016, but that 60 TB on a 3.5" is the absolute maximum attainable through the HAMR technology, in some unstated (but quite far away) future.