Well, let's try to compare like for like...
7950x = $599
7900XT = $800
64GB of RAM = $150
Thats' $1550 right there, before motherboard, storage, case, cooling, powersupply, etc. By the time you add all that (plus labor, either in dollars or in time) I bet you're in the $3500 range with those specs.
You have to consider the total package... the Studio is 7" x 7" x 4"... that's smaller than a microATX board, never mind some giant dual slot graphics card (Which also draws 300w btw, over 3x what the entire Studio draws).
Lack of noise, heat, and power efficiency has real value. Some of us are at a point where we want stuff that just works, not to fiddle with components and BIOs settings. Plus, frankly, nobody on the PC side has anything even close to Applecare.