The entire Mac line is only 10% of Apple's revenue. What percentage of that can be attributed to the Mini? Why would anyone be surprised that they aren't updating it?
https://www.macrumors.com/2018/05/01/2q-2018-results/
According to the
transcript of the 2017 meeting between Apple and journalists regarding the Mac Pro, Phil Schiller admitted to an 80/20 split between laptops and desktops. He clarified that Mac Pro users make up single digit percentage of that 100% - by definition that's up to 9% but clearly the iMac will be the lion's share of that remaining 20%
Somewhere in the middle of all that the Mini languishes. Filling the niche that shareholders probably demand. It could be that Apple might decide that an ARM powered Mac Nano comes along later down the line for hobbyists and tinkerers.
Realistically we're looking at desktops making up 2% of Apple revenue, with Minis and Mac Pros becoming a rounding error. OK, the reporting periods don't match so there's some assumptions made there but the logical thing for Apple to do would be to merge the Mac Pro and Mini which has been discussed here before. With Apple allowing a variety of AMD GPUs to be officially added as eGPU one view to take would be for the Mini to linger on as long as the Pro does before both lines get replaced by a modular Mac Pro.
Apple provide a main box with integrated graphics - large choice of internal memory and storage options, perhaps even SKUs with the AMD Vega graphics courtesy of the i5-8305g for example. Anyone wanting better graphics will go with eGPUs of their choice but AMD appear to be officially supported.
Consider for a moment if a new case were able to dissipate 140w TDP. And that could manage some or all of the following styles of SKU:
1. A very powerful Xeon - add your own eGPU because the case will be at the TDP limit
2. A 100w i7-8809G with AMD Vega graphics - eSports buyers wanting an all-in one solution.
3. A basic Xeon option with many drive bays for server use.
Rather than annually updating the modular Mac Pro because they have to keep up with GPU developments, Apple can leave that to people who want to upgrade their own GPU - externally. One possible source for delay could be PCIe 4.0 and the subsequent Thunderbolt 4 standard.
If you re-use the existing Mac Pro case we could see additional space within going towards heatsinks for prolonged silence, drive bays or cubbies for SATA 3 or M.2 devices. Or with a reduced TDP to look after, Apple could unify against a smaller case which will interest lower end buyers.
The only way Apple could accommodate a PCIe x16 graphics card into a modular Mac Pro design is if they felt that demand from Pro users was sufficient to include one. I'd say that their backing of eGPU makes it easier to design an enclosure with predictable heat dissipation and they'll not be including such a slot going forward.
They have upwards of a year for eGPU to mature well.