The MacBook line has been a mess for years now. There was a bad point when they had retina and non-retina versions for the whole Pro line. The iPad line is becoming pretty nuts. They simultaneously advertise the iPad Air 2, the iPad Air, the iPad Mini 3, the iPad Mini 2, and the original iPad Mini. Even iPhones are starting to suffer from this. It used to be obvious (either pick the best, or decide how much less you want to pay, then buy the one at that price) but now you have to figure out whether you want bigger or smaller, better camera or better pocketability, etc.
I like having more choices, personally, but Apple used to have a much more streamlined product offering.
Actually, there are 4 sizes of iPhone currently on the Apple store; 6, 6+, 5s, 5c. That gives you 3 different screen sizes and quite a few color and storage options. I find the current state of the Apple catalog to be depressingly complex and look forward to when there are 4 models to choose from; Business/Consumer, Portable/Desktop. But that's just me.
I think the problem is non-orthogonality. So many choices are bundled together, and you have to decide everything at once, instead of taking it one at a time. For a MacBook, back when the line was really simple, you'd pick a size, then pick a speed, pick storage, etc., more or less independently. All you had to control for at each stage was cost. iPhones were even simpler: pick a storage size and you're done.
Now, things are bundled together. If you choose an iPhone screen size first, you're implicitly choosing camera quality, materials, speed, fingerprint recognition, and such things all at once. If you like a plastic case (some people do!) then 4" is your only choice. If you want the best camera, you have to get a 5.5" phone even if that doesn't fit in your pocket. If you're buying a MacBook, you have to optimize ports, weight, speed, fancy new haptic trackpad, and other such things all at once.
Compared to other manufacturers, Apple is still doing pretty well here. But it's still considerably worse than it used to be.
This is technically true, but I think you're exaggerating the effects of some of the choices vs others.
For example, the difference in camera quality between the iPhone 6 and 6+ is minimal. Yes, if you are obsessed with 'the best' camera quality but want it in a smaller phone, you are faced with a compromise, but for almost everyone the phone size massively overshadows the trivial difference in camera. So people will pick the size they want and those who pick the bigger device will have the minor bonus of a marginally better camera.
Almost nobody obsesses over the full matrix of possible tradeoff the way you are implying. They just choose from what is available based on what is most important to them. The iPhone lineup is easy to select from based on this approach.
Yes, they could make things more orthogonal by say, not having the plastic phone, but it seems to me that this would have almost no effect of the ease of choosing, while just serving fewer customers.
I like having more choices, personally, but Apple used to have a much more streamlined product offering.