Not that I think writing a feature-complete shell is “easy”, but pipes, specifically, were the main feature of this shell implementation (besides reading, forking, and executing).

Probably a bit more than 35 weeks, if that POSIX control is going to be tested across multiple UNIX variants. :)

The video isn't advertising this as a shell you'd use in production.

It's an interesting resource to learn how shells work and are implemented. It doesn't cover absolutely everything, but it was never meant too.