The businessman is getting ready to risk the financial future of his company on a third party, the Computer Company. To do that, he needs to be able to regularly contact a responsible Apple manager who has the authority to fix a problem and fix it fast, and the businessman has to develop a long-lasting trust that that kind of support will continue for the forseeable future. From time to time, Apple mustered some of these elements, but never all of them for a sufficiently long time to impress the industry as a whole. As a result, you could buy a really cool computer from Apple Computer, but in too many cases, it did not appear that Apple Computer could be trusted to remain a stalwart, dependable business partner. If we look at Apple's focus today, it is on publishing and education.
Education is a very important market to dominate.
Apple is doing OK there, so it's not necessary to dwell on that. In publishing, Apple makes damn sure that the Power Macintosh is always faster doing anything with Photoshop than the competition. Time is money in publishing, and the general technical consensus is that Photoshop runs better on a Power Macintosh than anything else. But that is a very isolated technical bastion. Microsoft has been going after that market, correctly feeling that if they can trample the Macintosh in its one remaining haven of excellence, they will have won it all.