I really don't understand why more companies don't emulate Apple in terms of line simplicity. Look at Dell for a great example of a sprawling product mix. I can't imagine having that many product varieties helps with profitability.
In the consumer space, I recently bought a Sonicare toothbrush, and the number of models and combinations is staggering. 1000x plaque removal, 750% plaque removal, it's ridiculous.
Apple has a unique market position due to their OS. A buyer shopping for a Mac can't visit multiple vendors and compare models.
Dell and Sonicare do not have that luxury. They are competing with other PC vendors and other toothbrush vendors.
The strategy is to produce so many models that you appear to serve every price point and need without requiring the user to shop around. You can find something in their lineup that fits your budget or requirements if you look long enough and you don't feel like you need to go looking around at competing vendors as much.
Having may models isn't a high cost because they share so many parts. I bet if you opened multiple Sonicare toothbrushes they'd share many main components like batteries or motors. Dell has a few laptop and desktop lines but they're different combinations of parts within a shared chassis.
Dell's claim to fame when they started was they could manage the complexity of a large product mix to get you want you really need. It is a lot of work, but their ability to manage that complexity it what makes them profitable.
PC makers can't count on brand loyalty. If you want a PC and your favorite brand is missing something that a competitor has, it's easy to switch. If you want a Mac and Apple is missing something, it's harder to switch. Enterprise sales are a bit stickier, but not that much stickier.
So Dell, Lenovo, et Al end up trying to address every niche except the focused product catalog niche.