Because "simple" isn't always the same as "short." Even if you're not addressing the actual complexity of the answer (see Rule 4), breaking a complex concept down to where it's understandable is often not a short process.

Complex concepts are condensed things that often contain layers of foundational understanding, which then have to be unpacked for a layman to grasp the concept.

>4. Explain for laypeople (but not actual 5-year-olds)
>
>Unless OP states otherwise, assume no knowledge beyond a typical secondary education program. Avoid unexplained technical terms. Don't condescend; "like I'm five" is a figure of speech meaning "keep it clear and simple."