That's a really good point, but that may not be ideal from a pure learning perspective. Engineers are often subject to the whims of management, tight deadlines

That's a really good point, but that may not be ideal from a pure learning perspective. Engineers are often subject to the whims of management, tight deadlines, dependency quirks, their own personal bias, and so on. A living example would showcase all of those things, but unless you annotate each line and comment excessively, you lose a lot of context. It's also much easier to follow a tutorial than to dig through commit history and piece everything together yourself.