This is completely contrary to my experience, in which parser generators have not paid for themselves. Writing a parser by hand in C is generally easier and less time-consuming over the long run than struggling along with a parser generator, especially if you have any interest in producing useful syntax error messages or recovering from other kinds of errors in some useful way.

I agree that almost none of the important aspects of language implementation involve the parser - and that's why I write 'em by hand! It doesn't take much time, and it's much easier to debug whatever problems you run into when you can use your ordinary debugging tools.