I think that a case for having a very lean product line-up can be made from an engineering perspective as well. Having few SKUs and changing them rarely allows

I think that a case for having a very lean product line-up can be made from an engineering perspective as well. Having few SKUs and changing them rarely allows to focus on quality. It allows for very efficient manufacturing, since production is all about economies of scale. For already established product types, it enables iterative refinement. But perhaps most importantly it allows to put innovation focus on new kinds of products. The PC, laptop and tablet have all been invented and standardized. With the AirPods, Apple has again managed to establish themselves as a leading player (in affluent market/segments). They did the same with smartwatches a while back. Their track record is strong. Probably will do the same with... $FutureProductCategory. Of course this is only partly due to engineering and product design - brand building and marketing also vital components. And I think it is fair to say, that while a strong engineering organization, Apple is not engineering-driven. They consider engineering as a means to deliver good product, not an end in itself.