Marathon runner competes with no one but a time they want to be. Writer competes with no one but a standard they want to attain. Sustainable motivation requires following something we won't compete with.
Imagine a marathon runner uses the desire to beat a particular rival to spur them to train harder. What happens if their competitor drops out of the competition? If their motivation diminishes, it'd be hard for them to remain runners in the long term. Marathon runners who stick to running are usually motivated by an individual goal: a time they want to beat.
It's the same for being a novelist. For Haruki, there's no such thing as winning or losing as a novelist. Neither number of copies sold nor the awards won matter. What's crucial is whether his writing meets the standard he wants to attain.
This reminds me of Mimetic Theory (#33.4) because they both emphasize the significance of following something you won't compete with. Peter Thiel suggested we find a role model with which we won't compete. And in David Perell's, "If you're going to model a famous writer, pick a dead one such as Tolstoy or Hemingway".