&quot;To use a library effectively, you have to be able to write it.&quot;<p>That&#x27;s a blanket statement. If we find one exception to this rule, then we can say that it&#x27;s 100% false (since its truthfulness is binary -- it&#x27;s either true or false).<p>To find one exception, we only need to find a single &quot;good&quot; piece of software whose author can&#x27;t write 100% of the dependencies, including: (probably) C&#x2F;C++ compilers, FS drivers, low-level network libraries, and the widely-used monster that is SSH.