Prolific writers resource themselves abundantly. They invest in themselves and their writing. They work on great-functioning equipment, and in the best environment they can. This not only directly aids their productivity but sends an important message to themselves and others that their writing is important.
Underproductive ones, in contrast, are likely to be found working on crappy equipment in dank basements with the mold and spiders and last season's wardrobe.
Cartoons by the great Barry Deutsch.