Ignoring the final truth that of course everything anyone ever makes will one day be discarded, that's not the case in some industries.

Additionally, we had inspections. Every so often, the customer (or rather, the alliance of customers) would send someone. He would pick a handful of requirements, and would then ask to see the complete chain from there; the breakdown of requirements from their level to the more functional level, the design that purported to meet those requirements, the code that implemented that design, the tests of that code, and then the tests of the original top-level requirements. We would literally get the relevant envelopes from QA, open them up and give him the paperwork. Everything signed, stamped, cover-sheeted and ready. In some industries, this kind of traceability is required and if you don't do it properly up front, trying to rebuild that trace afterwards is extraordinarily expensive.

See my other big comment here somewhere; in that case, the majority of the code was written once, delivered, and will be in use for a few decades. It was generally written correctly at the first iteration; the "literate" bit, which was the discussion of design etc., generally didn't change, so even when bugs had to be fixed, only the code changed to more closely meet that design (i.e. take out the bug) - the design was still the same, so the literate bit was still valid.

It is common in some styles of programming (and/or some industries) to effectively plan in advance that you'll write a dozen bad versions that don't work very well and only then will you write it correctly, or that you don't quite know what you're making (be it because the requirements just aren't available properly, or because you're not building to set requirements but just trying to make something that might sell) so you'll just make something and keep bolting bits on as you think of new things, but there are other styles where the aim is to get it right first time.