No, the idea is sound and most probably correct. Companies that don't plan five years ahead are usually reactionary: they look to see what's happening in the market and look to take advantage.
Apple is fortunate enough to have considerable influence in technological trends, so yes, they will be planning and designing products that will not see the light of day for years. In many cases they will start to design products and wait for the technology to make them viable. The iPhone was on the deck years before it was released, or do you think that the thing was designed, engineered, programmed, approved, sold to the networks and then marketed in the space of a few months? If they weren't working on the iPhone while they were getting ready to release the first iPod then I'd be very surprised.
they weren't, they were not even working on the Ipad. After Steve got a capacitative touch screen he started work on ipad and then put it on hold and quickly switched to a phone for tactical reasons. Iphone itself wasn't in development for more than 2 years. You should listen to Aiden, he knows a thing or two.
Jobs knew (and learned the hard way) that you have to take something to market first as ready as you can have it, hence he rushed to release an iphone, a thin mac, an ipad, even if the first two were not ready for prime time (no third party applications, no email server like blackberry, frequent safari crashes, rudimentary phone software, poor call and voice quality compared to established players - and for the air poor hinge design, poor thermals, poor cpu performance, very compromised storage, poor overall design with a latch), but he did get there first and with apple's clout and marketing defined a category.
Apple doesn't plan ahead as much as they 'd want you to think, no one, as Aiden said can plan for 5 years ahead, this is just part of the apple mythology, because they want you to think they are that foresightful and inventive. They are not. And they can be as reactionary as they can be creative. How is it not reactionary when another device carves a space (kindle fire and android tablets) for a 7.something" tablet to eat up your words about sandpapering user fingers and prepare to launch a 7.something" competitor? How are they not "looking to the market to take advantage"?