If you're one of the majority of writers and relying on publishing for your income, you are probably not relying on publishing for your income but rather food stamps.
Many authors are their own publishers. Writing (and most arts) pays so little because society values their work so little. We seem to value a decent novel at about $5. An author already sees about $0.50-$1 of that. Respected, well reviewed, award winning (but not best selling) authors I know would still be hard up earning a living wage even if their income increased tenfold by them getting 100% of the proceeds.