Organizational pressure is a scarce resource, it's a waste to spend it on things that you can do with tooling. Keeping tests and sample code up to date involves more than just fixing compilation errors, sure, but the compilation error gets you reading and paying attention to the right piece of material.
Tests are not documentation. They only test a very limited "what" or "how" and give no explanation of "why". If it's closed source software and you're only shipping a binary, the tests do not go with the binaries so they're meaningless to third parties. Sample code isn't much better. Without the organizational pressure to keep it in sync with the code it's demoing and "why" explanations it doesn't provide a lot of useful insight for third parties.