Wow. I am impressed with just how profoundly you misunderstand the industrial design of a machine like this. Both the old aluminum anchor design and the new coffee-can design started in the same place: with the tech specs of the electronics, and the electrical and heat requirements of those components.Am I supposed to be impressed? Apple is probably the only company that uses pervert approach to design of workstations (and desktops too). Most other companies will start with tech specs like performance, memory/storage capacity, expandability etc. and then will design an appropriate case. Apple starts with the case (including the size) and then fits as much as they can into the can. Obviously the latter approach guarantees most compact design. The only problem is when you need to actually use these toys.
One design used multiple cooling channels, each with a variable-speed fan, to minimize the noise needed to keep the components from getting hot. (The heat output of the PPC G5 was not pretty.) Size wasn't a consideration, and making it big was in fact welcomed to allow internal expansion.
The other design emphasized used a single cooling channel to serve all of the components, which required a compact design that put them all within heat-conductive reach of it. Internal expansion wasn't a consideration, leaving that to external add-ons.
Same starting point, different priorities, but the same methodology.
Both can be contrasted with the design of a typical desktop computer, which follows the principles pioneered *cough* by IBM back in 1980: put them in a big enough box, and add fans here and there as necessary.