However I bristle at the idea that core design decisions are usually super obvious, even when the end results are. Not sure this is even your point so forgive the tangent if not, but this issue is my particular hill to die on, it's 100% the single biggest gap in understanding that I see between those that regularly engage in original creative work vs those who do not.
People see something obvious and say "That's simple, I could have come up with that!" But that's all hindsight, like saying "I could have bought bitcoin in 2010!" It's not even wrong, it's answering an entirely different question of capability, not probability.
The question is would you have come up with that, were you tasked with the problem and put in the same context? I'd estimate for most great-but-simple inventions, it's not many people who could plausibly say that, because so much of what we bring to bear on problems comes from our own histories and unique perspectives & influences, not to mention talents and predilections.
This distinction between could vs would is core to understanding creative output, especially the ideas that are the simplest to use or understand. The delta between understanding vs coming up with there is often vast; simple things are often the hardest things of all to conceive.
