This is a textbook for a university course. The intended audience for this book needs a bare minimum compiler, because that is all they will have time to write

This is a textbook for a university course. The intended audience for this book needs a bare minimum compiler, because that is all they will have time to write. You can't just say "use a parser generator". Who is supposed to write the parser generator, then? This book is for people who want to learn how to do all that foundational stuff, not an industrial programmer who needs to build a good product quickly.