I've never interpreted "Premature optimization..." to mean don't think about performance, just that you don't have to actually implement mechanisms to increase performance until you actually have requirements to do so - you should always ask of a design "how could I make this perform better if I had to".

To me, it rather meant: "Ultrahard" optimization is perfectly fine and a good idea, but not before it has become clear that the requirements won't change anymore (because highly optimized code is very often much harder to change to include additional requirements).

Any different interpretation in my opinion leads to slow, overbloated software.