>theoretically perfect design

We have no metric to use to quantitatively score one design as something unequivocally better than another design.

This is the first thing you will need before you can prove one "design" is "better" than the other. Until than we are doomed to go in circles and have endless debates.

I believe even if we do find some quantitative measure on program "designs" it won't be rating something as "better" or "worse" it will likely be metrics on many dimensions measuring tradeoffs.