Novels still have a good standing with the 'novels we love curated weekly' section and the popular and trending shortlists that appear alongside the comics. As for the other lists, it's kind of representative of the overall comics to novels ratio on the site? There's like 70,000 comic titles and just about 10,000 novels or less if my memory serves correctly (I believe someone listed it once in the forums somewhere).
The novels section is 3 years old compared to the 7 years head start comics had on this site, so it will take time to catch up.
I also believe that they don't want to add too many sections to the homepage because average consumers will stop scrolling after a certain point, and that point's pretty short on the low-attention-span internet.
Of course it could be remedied if the sections switch out every couple of months or so, but I don't have site metrics so I can't say if they found it to work in the past or not.
As for
This is pretty much for business reasons. Tapas has to keep the lights on one way or another. They also need a return on investment. As Tapas grows, their expenses get higher (server space, hiring people, etc), so they have to focus on projects that would pay their bills.
