Speaking as someone who talked to six different presses about doing my graphic novel, roughly 90% of all the small-press stuff is self-financed.
It used to sort of work out - you spend $30k getting a book illustrated and putting out 5,000 copies. 2500 of them get bought at $10. You get 80% of that. Turns out you're only about $12k in the hole on your book and if that means you get a movie option out of it, you made a hell of a brilliant investment. Lookin' at you, 30 days of night. Wanted had sold less than 10,000 copies at the time Timur Bekmambetov optioned it.
That was the universe that existed before Disney made eight fucking summer blockbusters to justify the Avengers.