As others noted, the Dragon Book spends far too much time on parsing, and not nearly enough on optimizations. To be fair, the first edition of the book is from 1986. It looks like the 2nd edition (2006) adds 3 chapters on data flow analysis, parallelization. I don't happen to have that version of the book so I don't know how good the material is.

I took compilers in grad school in the early 90's. Even then, we mostly skipped parsing because that was considered covered in another class (Theory of Computation, a class that covered regular expression, finite automata, Turing machines, P vs NP, those sorts of topics).

The professor spent as much time as he could on optimizations, since that was his research focus. He then went onto write his own compiler book (Engineering a Compiler; Cooper & Torczon) so you can compare the table of contents (https://www.elsevier.com/books/engineering-a-compiler/cooper...) and see what current compiler researchers feel are important topics to cover in a textbook.

Not throwing the Dragon Book under the bus, but it probably is in the "cited widely but rarely read" category as you have noted, just from its position as being first/early.

An anecdote from me - I had the occasion to write a parser for a work project a few years ago. Rather than reach for flex/bison or any theory I had from compiler courses... I went with the new-to-me method of a parser combinator. This was awesome and I might even describe as fun. Granted the target language I was parsing was much simpler than a programming language, but I hope that is covered in today's compilers courses. I remember really tedious parsing homework problems back in the day.