>which has been used for writing books for decades

Well, mostly math and science books. Very few (if any) fancy and well typespeced books by major publishers have been made with LaTeX. I know, because I know that industry. So, while TeX was once created to be a general typesetting solution, it has been relegated to something math and cs geeks use for their papers.

>And if you find LaTeX is so hard, there's always LyX...

A not really maintained, relic of a program, that tries too hard to work around the issues raised by a backend like LaTeX that wasn't really created with such GUI control in mind.