I don't know where these people are getting this bit of information from, but they're claiming that Steve Jobs "worked for more than a year on the products that he believed would safeguard the company" during the next four years.
Four year plans seem normal to me—any company should have a roadmap for at least the next four years. It's only logical if they want to make strategic decisions that would give them benefits in the long term.
Apple is a perfect example of this: they made contracts well in advance to secure a steady supply of low price flash memory and touch screens over the next several years. They did it for the MacBook Air, the iPhone, the iPod touch and the iPad. That's why their prices are lower than the rest of the industry and their margins higher, as Tim Cook reminded everyone last January:
[...] we have historically entered into certain agreements with different people to secure supply and other benefits, and the largest one in the recent past is that we signed a deal with several flash suppliers at the end of 2005 that totalled over a billion dollars, because we anticipated that flash would become increasingly important across our entire product line and incredibly important to the entire industry, so we wanted to secure supply for the company.
Long-term plans are also needed to guarantee smooth research, design, development and manufacturing phases. In fact, during the same conference call Tim Cook admitted they were spending lots of money on something they couldn't reveal, something looking "way ahead."