The prolific tend to see their writing not as some holy mission but their “work, “craft,” or even “job”:
Stephen King: “Don't wait for the muse...This isn't the Ouija board or the spirit-world we're talking about here, but just another job like laying pipe or driving long-haul trucks. Your job is to make sure the muse knows where you're going to be every day from nine 'til noon or seven 'till three.”
Anthony Trollope: “Let [other writers] work be to them as is his common work to the common laborer. No gigantic efforts will then be necessary. He need tie no wet towels round his brow, nor sit for thirty hours at his desk without moving — as men have sat, or said that they have sat.”
(Love the skepticism at the end of Trollope's statement, which I think is entirely justified when reading grandiose statements about writing.) Ironically, it's the nongrandiose attitude that frees writers to consistently experience the glory and transcendence that grandiosity promises but only rarely, if ever, delivers.