When you're paying the sort of premium prices that Apple are currently charging, you're entitled to expect "up-to-date". That doesn't mean the latest gimmicks - just the best currently-available CPUs, GPUs etc. and enough expandability to upgrade (at least) RAM and storage affordably, so it will keep 'doing the job' for as long as possible. If I'm going to economise on spec, then I expect to economise on price, too. I'd apply the same to other "premium" models - such as MS Surface Book/Studio etc, except that if you're prepared to give up Mac OS there are lots of far more cost-effective ways to run Windows or Linux.
Anyway, I think this whole discussion misses the point about the Mac Mini's size: the Mini form-factor was designed to accommodate an optical drive
and a 2.5" mechanical hard drive (or just 2 2.5" HDs) - it should be
swimming in space now those are no longer needed, but instead Apple decided to switch from mobile processors to desktop processors, which meant that space which
could have been used for internal expansion had to be sacrificed for a larger PSU and more cooling. That decision also limits it to a lowest-common-denominator iGPU only intended for "business graphics" (since any other desktop would have space for at least an entry-level PCIe GPU) meaning that you need to start thinking about eGPUs even if you just want to run a couple of 4k displays for 2D work at scaled resolution.
Seriously - I can see the role of eGPUs in supplementing laptops, but the idea of desktop systems relying on them is just plain potty when you could have everything in one box not much larger than the eGPU
or the option of a Mini with a decent mobile processor and high-end iGPU (or maybe the hybrid Intel i7 chips with discrete AMD GPUs in the same package) that had a better balance between CPU and GPU power.
Hey, why not have a box with
just a PCIe-like bus and power supply, into which you could slot separate CPU, storage and graphics cards to build a system that suited your needs without a tangle of separate boxes, cables and power bricks? You could call it, I dunno, the "S-100 bus" or something...