An entirely evoultionary approach would only be able work on the information that the design was a failure, not why.
So no different from the example of the soap powder nozzle above then, which I note those people against the OP analogy seem to be conveniently avoiding.
I understand and appreciate
EVERYTHING that you and ID, in particular, have written, but can you not envisage a scenario whereby a known complex machine could have become what it is from its most meagre beginnings, just by the engineer (designer, if you like) saying:
"OK, I'll make some random changes to the length of that part, and/or to the composition of that material, and/or I'll introduce this additional basic component. I'll then trial it, and if it works better than before I'll retain that particular change. If not, I'll make a different random change and see what effect that has. Then I'll do the same again, repeatedly. Actually, I might even start with a number of basic prototypes and randomly change them all in parallel. If I get to a point where one 'model' is clearly increasingly lagging behind the others in terms of its functionality then I'll discard that one and just proceed with the others."
Can you not see how this,
GIVEN TIME, could conceivably result in the creation of some of the complex machines we see around us today?
The only difference between this scenario and reality is that we have acquired the benefit of foresight, and we can
SHORT CIRCUIT (and that's all it is) the evolutionary timeframe by predicting in advance what might or might not work better rather than by physically trialing it and seeing what the environment informs us works better. To my mind that's all that design does; it speeds up the time taken to create something that natural evolution could, given time, naturally create anyhow.
We all know the complete works of Shakespeare/monkey/typewriter analogy. Stretch that a little farther and it's not unreasonable to conclude that,
GIVEN ENOUGH TIME, every
POSSIBLE physical scenario that could arise would eventually arise, including the creation of every possible alternative for every possible machine already and yet-to-be created through simple trial and error.