No kidding. Who ever said anything about not knowing what the requirements are?
The point you were disagreeing with here was "80% of the software an engineer will write will not require optimization". ie, 80% of any given system hitting the performance requirements naively. So... why are you still arguing?
Because blind adherence to the "Make it work then make it fast" advice has been the bane of my career.
Generally speaking, I have not found it to be true that you can make something fast if you didn't think about performance first. If you thought about it, and came to the decision "it will be fast enough no matter what we do" bully for you, but for me that happens way less than 80% of the time.
The point you were disagreeing with here was "80% of the software an engineer will write will not require optimization". ie, 80% of any given system hitting the performance requirements naively. So... why are you still arguing?