Apple doesn't want people to buy the Mini, but they don't particularly want to turn customers away, either.
The current Mini (maybe with an incremental spec bump) seems to fill the "cheap" category OK.
I think what most people here are pining for is the option of a
powerful Mac Mini that they had pre-2012. The problem there, though, is that it's a small, niche market that would be expensive to develop - requiring lots of bespoke components and clever cooling systems. Rivals like the Intel Skull Canyon NUC are already pretty expensive for the power (and they lack the Mini's killer feature of having an internal power supply which makes the cooling even more fun).
I think that what they
should do is re-visit the "xMac" affordable/expandable mini-tower concept. The argument against this, was that it would cannibalise other sales. I think that was quite true - years ago - nowadays though, most consumers
want ultrabooks, all-in-ones and convertibles - the only people buying towers/headless systems are those of us who have a reason for needing that format.
The advantage of an xMac is that it would be dirt cheap to design, produce and keep up to date - just a regular MicroATX or MiniITX motherboard in a nicer-than-average case (they could even outsource it). It wouldn't sell in great quantity, the point for Apple would be the strategic one of keeping power-users and enthusiasts happy - because the way Apple are going at the moment, they'll soon be jumping ship to Windows and Linux.
The other alternative would be an "official" Hackintosh program: say, $150 for a license to run the current OS X version on 3rd party hardware (strictly not for resale), access to an official list of supported hardware (at chipset level) and the security to know that you won't get bricked, lose updates or have your Apple ID suspended because Apple suddenly decide to crack down on Hackintoshing.
Trouble is, both of these involve the top brass of Apple seeing the value of keeping the power-users happy: they may be a minority, but they're the ones that provide unofficial support to friends family and colleagues, evangelise Mac to others, keep Macs alive in PC-biassed workplaces, write software & create a market for specialist software on the Mac.
Unfortunately, it looks like the current top brass lack any genuine enthusiasm for Macs. We all understand management speak: if they
need to say "The Mac is very important to us" it can only mean "We don't give a wet slap about the Mac and will be dumping it as soon as we find a good exit strategy".