its about continuity...***the following post is merely speculation and does not show the exact opinion of the author
the hobbit had all male charactors(mainly because the absence of dwarf women...i just thought of something hmmm...)^ anyway so the hobbit became very boy oriented and lotr became geared towards booys in a time lets face it women were too busy cleaning and cooking to read. so the lower showing of women.
^look in i found the entwives for my off-topic thought