@Sam R I think the major problem here is that people are not excited enough to buy new Macs; is this a hardware issue, a software issue, or is it both?
This is a late 2012 Mini with 10Gig and a reasonably-sized SSD in addition to the internal drive. Why would I need to change it? Where's my motivation? It has the mobo connectors so a second drive could be added, likewise the memory was upgraded when I got it off eBay.
I've not tried Mojave on it yet but assume it will run.