I’m not sure this is the best way to think about computers (and especially Macs).
First, like @Ulli suggested, many people use Apple devices for the operating system. I’d extend that to the whole Apple ecosystem. Many of my recreational/personal Mac users feel this way. They’ve used Windows throughout their careers, so they’re familiar with the main competition. And they choose Macs because of the integration that designing the hardware and the software brings — and if they want a tablet, the iPad is the only thing worth considering.
Second, people don’t buy a computer because 80% of the hardware fits their needs. Usually, its one or two things that they consider a requirement, and everything else either comes along with it or they go with the cheapest option.
For example, some people want an all-in-one desktop. So, that means an iMac. A cheaper MacBook Air with lower specs is irrelevant. Some people want the largest screen they can get, which might mean an iMac or a Mac Mini with a non-Apple display.
Other people want a laptop, but they have an extensive photograph collection. They will be best served by a hard drive that’s large enough to hold all of their images, with room to grow. If they’re a hobbyist photographer, they will increase the RAM because they’re in the Adobe ecosystem for data processing. Large hard drives are often available only on the higher-spec machines.
And don’t forget the perils of running old hardware! Many of my clients don’t care about keeping their Mac updated, but they do keep their iPhone updated. If they use an Apple ID on that Mac (I’ve yet to come across someone who doesn’t), they will inevitably experience problems keeping the data in sync if the Mac falls far behind in updates. And once a Mac stops receiving major OS updates, its days are numbered. That usually takes 7 years or so, and quite a few of my clients prefer that. When they replace a Mac, they will slightly overbuy, so they feel they can get another 7 years out of it.
You could argue that this “overbuying” is a result of Apple’s limited hardware choices, and you’d be right. But I think it’s pretty obvious that this isn’t necessarily a bad thing. Apple keeps its hardware line limited so it can continue to be profitable in the Mac sector. They tried licensing to create an ecosystem like Windows, and they couldn’t do it any better. I had a PowerComputing Mac, and while it was great to be able to get all of that power for cheap, it was not a reliable computer.
As for Chromebooks, they’re not equivalent to a full computer. They rely on a connection to the internet for everything (computing and storage). For example, there is no iCloud for Chrome (like there is iCloud for Windows). That’s a deal killer for my clients when I explain that there’s no easy way to automatically have all of their (iCloud) photographs synced to a Chromebook at full resolution (to act as a backup in case iCloud ever has a serious problem).