Schiller: "The MacBook Pro uses 16GB of very fast LPDDR memory, up to 2133MHz. To support 32GB of memory would require using DDR memory that is not low power and also require a different design of the logic board which might reduce space for batteries. Both factors would reduce battery life."
— Phil Schiller, per MacRumors
Well, Phil, use DDR memory in a bigger, heavier body, redesign the logic board, increase the size of the batteries as well—and then rightly call it a "Pro" model. Not everyone at the coffee shop will want one, but professionals needing the horsepower will accept and understand the limitations in weight and battery time, etc.
While at it you might make this something like a dGPU, in that it can switch automatically to a lower power mode, and components, when not needed. As for running the battery flat, have the option for the MBP to turn itself off before that point. Etc.
Why am I telling you this … are you not the experts?
Apple has never made a laptop like this so while you are free to wish for anything you want, you should do yourself a favor and frame your expectations based on the known history.