What does this quote say about Santiago: “I could just drift [...] and sleep and put a bight of line around my toe to wake me. But today is eighty-five days and I should fish the day well"?

In The Old Man and the Sea by Ernest Hemingway, an aged fisherman has gone many days without catching anything, and as a result, he is regarded as unlucky, and the boy who befriended him is not allowed to fish with him anymore. However, through his simple but intricately detailed style, Hemingway makes clear that the old man is in fact a very good fisherman with an intimate knowledge of all aspects of the occupation, his equipment, and his surrounding environment.
The line "I could just drift..." is the beginning of an integral passage, coming as it does just before he hooks the immense fish. It highlights the old man's character and determination. When it says, "I could just drift, he thought, and sleep and put a bight of line around my toe to wake me," Hemingway reveals a moment of temptation, an easy answer to the arduous task of putting his entire focus and strength into his fishing. However, the old man quickly resists this temptation when he thinks, "But today is eighty-five days and I should fish the day well." He is acutely aware that despite the skills he has developed over many years he has not caught a fish in a long time, and he is determined to do his best whether he succeeds or fails.

This quote occurs on day two, paragraph 54. It actually makes up the entire paragraph, and it is an easy quote to just gloss over and not consider its importance. The quote shows readers a great deal about what kind of man Santiago is because the quote speaks to his unceasing perseverance in his craft. He isn't a lazy fisherman. He works hard at his occupation, and he simply refuses to give up. The fact that it is day 85 without a catch actually serves to focus Santiago even more. He doesn't have a sense of hopelessness. He has a determined focus to persevere, carefully watch the water, and get himself a catch. Santiago's efforts are actually immediately rewarded in the following paragraph. He sees his lines move:

Just then, watching his lines, he saw one of the projecting green sticks dip sharply.