There is a lot of wishful thinking that goes into galaxy brain code. It assumes you know with almost complete certainty what rules are bound to change and where extension will be needed, that the next developer will be able to understand and respect the beautiful elegance of the design instead of hacking at it to achieve the desired result, and that the code will be long-lived enough to justify the initial investment. Grug coders aren't always inexperienced; many are actually repented architecture astronauts.