I'm not a 'long writer' and have never wanted to write a novel or even a novella. Poetry, like flash fiction, provides a readily accessible canvas to play with. Whether to express an emotion or share a vignette, these forms are often interchangeable.
Melville locked himself away in his room for months while working on 'Moby Dick.' If I ever decide to write a novel, I hope someone will take pity on me and take me out to dinner instead.
I'm a happy camper when I'm doing both: writing and art every day, along with a dose of reading and adventures into what else is being done by other artists/writers and poets. Like breathing. I've written poems or fictions to go with a painting. The source for the inspiration of the art often eludes me.