You need the 128gb ram config to get the 614 GB/s bandwidth (which is $6999), you could skip out on upgrading the storage to save money but at that point I think most people upgrade the storage too at which point it's $8-10k + tax.
Why are you throwing in extra cost for something thats not necessary? I know multiple people with 128GB Macs and none of us upgraded the storage. Especially not on a Studio (which isn't currently available).
I will say that their $3k number is off. I somehow missed that, and its too low.
Still 3x lower memory Bandwidth than a dual 3090 setup which you can build for $3k with parts from facebook marketplace and run in your basement.