No, it doesn’t fund full time because the advance isn’t paid all in advance! It’s often paid in thirds or even fourths at the this point, with the final payment not occurring until well after the book is published. So like one third on acceptance, one third on editing being done, one third once the book hit shelves. Or one fourth on acceptance, one fourth on editing, one fourth on hard copies being out, one fourth on a soft copy being out. Even with a six figure advance, you are not getting 100k that year, maybe 33-66k depending on how slow your editor is, and of course your agent takes a bite out of that, and you pay a high tax on it too.