Even if you write a really good novel, and even if you succeed in getting it published somehow, it will most likely be read by a vanishingly small number of people. The celebrity authors who write the best-sellers are the lucky (and talented) few, but they are vastly outnumbered by the unlucky (though still talented) many, and the even more numerous would-be writers who are neither lucky nor talented.
So what does this mean to a hopeful novelist? It means that you should never write a book for the express purpose of making money, because it probably won't. If money is your thing, there are much easier and more reliable ways to get it. The only reason to write fiction in the current publishing climate is because you have a story you feel genuinely compelled to tell. If you feel you just have to get it down on paper, then by all means do so. But do it for the sake of the story itself, and let the chips fall where they may. If you talk yourself into thinking you're going to be the next JK Rowling, you will almost certainly be disappointed.