Yes, if you take away all the reasons they are a fad, then they are not a fad.![]()
Touche!
I'd like Apple to either update the Mini or even offer a decent mid-tower, but when you look at the typical specs of consumer-priced PC mid-towers, I have the greatest doubts that Apple's mid-tower Mac would be anywhere near as viable compared to their iMac range. It'd surely risk having either low-sales or unacceptably low profit-margins.
Compare today's consumer iMacs with PC AIOs & we find Apple offers an excellent deal for the price, even without OS X. But PC mid-towers, unlike PC AIOs, are a very small profit-margin product indeed. This would pose immense problems for Apple's general philosophy.
If Apple released a mid-tower, then in order to maintain viable profit margins according to Apple's business plan & still remain price-competitive, it'd be seriously under-specced compared to their PC counterparts.
Imagine the scenario: Apple releases mid-tower Mac with middling video card, no BR, less this, less that, etc. compared to most similarly-priced PCs equipped with 8800 cards, BR drives, etc. This could seriously backfire. The Mini, though under-specced, holds it own partly because of it's unique size. An Apple mid-tower is unlikely to have that appeal, certainly not without all sorts of extra bells & whistles, & then it risks being seriously over-priced.
Releasing a mid-tower Mac would certainly satisfy a small, but significant segment of the Mac market, but it'd either have to be over-priced to maintain Mac profit margins, or else it'd be seriously compromised. Thus, IMO, an updated Mini with better BTO options may be a better way of catering for those presently dissatisfied with the Mac range.
FWIW, even though 1 of my 2 Macs is an iMac, if Apple released a mid-tower, I'd consider buying one. I'm not saying it wouldn't be personally desirable. I'd love to see it happen just to see how the consumer market responds. I'm just giving an opinion as to why it'll never happen under Apple's/SJ's current thinking.