I think the point here is that this mouse is supposed to be an advancement in technology, not a regression.
There are plenty of situations, for example when using CAD or 3D software, where being able to click more than one button at a time is a serious aid to productivity.
Just because you, in your limited capacity, don't need a middle button, don't assume that this is the same for everyone.
Lots of people actually use Macs for serious work, not just as toys as this 'magic' (mickey?) mouse would seem to indicate.
Apple would be irresponsible if they shipped a mouse designed for professional uses with each Mac and saddle the vast majority of their users with the extra cost of a device they don't need. The mouse they ship is appropriate for the 90+% of customers of "limited capacity" (a rather condescending description of the majority of computers I'd say.)
A 'superuser' mouse would be confusing and useless to the vast majority of users. If you're doing CAD/CAM or 3D, you need to act like a professional and get the tool that's right for your 'limited focus'. I don't want to pay extra for a tool I don't need.
I personally see the touch interface to the mouse as quite an advancement.