Fundamentally, you’d think that, if there were any real interest for this idea, some PC manufacturer would have already tried it. So far, we’ve got a market size of only one, and his grounds for advocating for the idea seem to have some serious misunderstandings of critical aspects of how computers work (and how cable management works, for that matter).
You’re going to face thermal constraints in any passively-cooled fanless computing device. If anything, the thermal restraints on a pocket sized computer are actually worse than those on a decently sized laptop.
In addition to the thermal constraints, you keep on going on about these laptop misconceptions of yours, details that are no longer true or were never true in the first place. A 15” MacBook Air is probably more powerful in a fanless design than this Mac Liberty idea would be and would look far more professional than your silly idea of a pocket sized battery powered Mac. And clearly, the general pro market doesn’t share your hangup, given that Apple laptops have outsold desktops since even before the Intel era (long before that became the general trend industry wide).
Finally, the cable management point, I’ve never once had the issue of the Mac mini coming unplugged when I remove peripherals. Of course, I’m not also transporting the Mac mini repeatedly from place to place, but, if I were, I’d buy a laptop. Get the right tool for the job, IMO.
The reason people are hating on your idea is that it only makes sense to you, and it only makes sense to you because you’ve got some old misconceptions and flat out ignorance about computers combined with a pretty serious case of confirmation bias.
As for the general idea of a small battery as a quasi-UPS for the Mac mini, hm, maybe there’s some merit, maybe not. You’d have to add the battery, as well as the battery management unit. Capacity-wise, it wouldn’t have to be a large battery (just enough to give a 20% margin over the power needed to put the computer into an unpowered hibernation mode), and you could get away with only charging it when it becomes discharged (but you’d have to have great standby life for that, otherwise the battery would fail without even getting used). Basically, as soon as the computer detects that it’s operating from battery power, it would begin hibernation mode. Sell it as a BTO option (labeled as a consumer UPS perhaps) for locales with poor power stability (maybe California, with its tendency towards brownouts).