Apple works under the guise of a niche market. Every one of their desktop lines offers something that the average desktop does not. The mac mini is really small. The imac is an AIO..which is rare. The mac pro has 2 processors and 4 hd slots. There is no "normal" non-niche desktop machine available. Why is it that apple makes niche products instead of mainstream products? Fear of the competition. They can't compete with desktop tower PC machines, so they spice up their line with creative designs. While formwise they look great.....functionwise they are lacking compared to their PC counterparts.
If apple licensed osx...which they would never do b\c they lose to much money...who here would build their own mac or buy a competing company's product with osx installed? Is having a faster computer for half the price worth a slight aesthetic loss?
My point was never..is it economical for apple to make a midrange tower. It doesn't matter. There is no way anyone here even knows if it is economical. You don't know the margins or have access the apple's financial information. My point is..do the consumers want to accept a midrange tower for an adequate price?
I'll agree with you that Apple desktops languish a bit behind PC makers.
However, you last point about econimics is way off. I posted above that the risk for more options doesn't lie with the consumer, it lies with the business. There are always going to be a few people, like you, who will want a Mac tower. However, if we were to compare that number to the total number of people who really don't care about a tower, it will be dwarfed. Now, you're quite right in saying that I don't know this for sure; I don't have access to information like that, and I'm not privy to any insider information. However, given what we know about the desktop market and its near future and the fact that Apple has ignored this market for some time gives us some good clues. Remember, Apple is very aware of its size and its potential. It took a lot of research and forsight for Apple to launch a product in a very competitive field. I'm refering to the iPhone of course. Don't assume that Apple hasn't thought of this tower. That company has a lot of well educated, intelligent, and hard working people at its disposal, and their information eventually led them to believe that the tower market wasn't one worth entering into. I know you want to believe that this is a demand-side question, but I'm telling you it's not. This is very much a supply-side question. Can Apple afford to enter the tower market: probably not.
So, I'll provide a summary:
A small percentage of the population wants towers of the kind you describe.
A smaller precentage of that population wants towers of the kind you describe with OS X.
Thus, the OS X tower market can be described to be a "niche" at best.
Apple, a company which has to be selective in its product variety in order to maintain good margins, chooses not to develop a tower of the kind you describe.
This final point isn't based on cold hard facts, but based on Apple's actions over the past couple of years, and the fact that we know Jobs and Co. are no fools. They know what they're doing, and they're doing it quite well.