The IEEE was wrong with their estimates. CBM insiders have said that the cost was about $35 per unit later in the run. The original cost was $135 when introduced, five dollars more than the planned cost, and the computer retailed for $595. With a 30% discount to the retailer, CBM easily made a lot of money on the C64.
Of course, it helps when you have your own chip foundry and your competitors are also using your microprocessors for their computer.
How you take the world's largest computer company and run it into the ground in ten years is another story.