An important factor to note is that it's rare for anyone to sell a first novel written before they turned 30-35; long-format fiction tends to require a bunch of experience of human life that takes time to acquire. So your average mid-career novelist is in their forties to fifties!
Charles StrossA religious college in Cairo is considering issues of nanotechnology: If replicators are used to prepare a copy of a strip of bacon, right down to the molecular level, but without it ever being part of a pig, how is it to be treated?
Charles Stross