It does seem like a self-fulfilling prophecy going on here.
Why doesn't Apple update it's desktop line more regularly? Because not enough people are buying them.
Why aren't people buying them? Because they are not updated often enough.
Why doesn't Apple update the Mac Pro? Because not enough people are buying them.
Why aren't more people buying them? Because they are incredibly out of date and overpriced.
I suppose it's a combination of self-fulfilling prophecy and the chicken/egg problem. All that aside, the new mac mini is almost certainly coming.
Part of this is down to Intel's CPUs reaching a plateau ever since the Sandy Bridge CPU. They are very good indeed but we've had 3-4 generations ever since which shows a relative lack of innovation aside from process shrink which reduces power consumption but shipping dates are constantly slipping as the process shrink becomes harder. Bottom line is desktop buyers are holding on to their machines for longer.
The bigger updates are coming from replacing hard drives with SSD (or Fusion drive) and improving GPU compute using Iris Graphics or a GPU. We're seeing an occasional transition in connection standards with the Thunderbolt that could just annoy users who invest in TB gear.
Done right, there's no reason for most users to update a desktop PC for years and when they do Apple are handing over a lion's share of the money to Intel for the CPU. Apple really need AMD Zen to be good if for nothing else but to keep Intel on their toes. The fact that Apple are heavily into Thunderbolt makes a switch to Zen itself unlikely.
It's no surprise that Apple are soldering down the components - cheaper to manufacture but preventing users from making their own upgrades which bypass Apple anyway - these users (plenty to be seen in the Mac Pro forums too) are keeping their computers for 5-6 years. I've accepted that I may as well have some sort of external storage to let Apple get away with a thinner computer.
Until recently updates to Macs were fairly predictable meaning people could save up money and spend it on the annual iMac refresh, for example. It really doesn't help when Apple start missing the predicted deadlines, raise prices, produce outdated gear and then folks start spending their money on generic PC gear to Hackintosh or just go Windows 10.
On the other hand, we're still in the Microsoft zone with iPads where the latest annual iOS update performs relatively poorly on older machines which prompts users to buy newer devices more often.
Add this to the different sizes of screens, ever thinner and lighter devices with CPUs that still make quantum leaps in performance in a package which makes Apple more profit every time and you can see why want people to have iPads and combine them with iCloud.
The fact that they change form factors offers users something tangibly different to consider every few years. We've gone from 9.7" to 7.9", up to 12.9", perhaps down to 10.5" with smaller bezels. All of them getting lighter each generation.
Some people are saying that Apple will be using a later Ax series ARM CPU for future desktop devices, and they may well do so for something in the future (tied exclusively to an Ax Mac App store in my opinion) leaving people who need Intel to fork out for a Pro device. I'm not so sure that's coming in the short term.
Apple's premium pricing plan on Macs (never discounting across the on-sale life of a model) helps keep used values high. If they think they have too many SKUs versus sales per model they just need to simplify their models line-up.
They need to accept that they should have a new design every 4-5 years with predictable speed bumps in between if they are going to insist on keeping that price the same between models.
Or stop making people hang on with a dead product and discontinue the Mini. Let people move on with their lives rather than hanging around in this thread
