Of course, the negativists are saying "gee, if their sales are locked in for the first five years of production, as their chief sales goon claims, why are they advertising?"
IIRC, that was described in the book The Soul of A New Machine. The advertising isn't there to get new converts as much as to keep and maintain the "pride" (for lack of a better word) of the owners and keep them "in the family". If everyone else is running nice spreads and your chosen system isn't, it makes you feel like you bought in to some 3rd-tier computer.
I always wondered why Commodore 64 was adverting in magazines that were about the C64. In that case, I think it was a way of supporting the magazine, but I also see the point in keeping the owners happy with their choice.