what's the point of FP if processors are still Von Neumann?

You are shooting yourself in the foot by thinking in a manner inconsistent with the computer.

I get it. The FP attitude to programming and computers is they hate them. They don't understand why there should be some sort of calculating machine, and why they should pay attention to its lowly details such as memory consumption and what evaluates how many times. They don't believe software engineering should be a profession. The FP approach to computing is they should be able to express themselves in the language of pure mathematics and some magical jinn should just jump out and give them any answer they ask.