Perhaps you are implying the Dragon Book is not needed for people who will use tools like lex and yacc to generate it.
While that is true, the Dragon Book gives real insight into how a compiler really works and how to code one from scratch. If someone is only interested in getting a very basic compiler up and running quickly and not interested in understanding how to really make one, a simple tutorial for yacc should suffice.
If you're really making a compiler, it's unlikely you'll use a parser generator. Most production compilers use hand-written parsers for a variety of reasons: speed (e.g. folding more logical passes over the AST into the AST construction in the parser), semantic resolution of grammatical ambiguities, flexibility for compatibility (e.g. toggling different syntax rules dynamically), etc.
But such detailed info isn't necessary even to write a compiler front end. It's good that the treatment exists, and that it's in the dragon book, but it's not what you need, even for parsing.