I have quite a few books with a pretty cover, pictures, charts, pullquotes, etc.

LaTeX predates HTML by a decade and supports pictures, charts, quotes and far more, and doesn't force me as an author to make finicky decisions about presentation. I just write the content, and then set the document class to whatever the publisher wants.

Who reads books with no tables, graphs, images, or maps? ;)

My immediate thought was The Machinist's Handbook or a similar publication for chemistry that is pretty much all tables.

Have you any idea how much work goes into typesetting a book?

Presented 'like a book'. Its a blog, not a 400 page novel.