The narrarator says " He (santiago) took his suffering as it came" How long had the battle been going on and why did santiago not just cut the line and put an end to the suffering and hardship?

Santiago battles the great Marlin for three days. Santiago had to keep fighting. The struggle became a metaphor for Santiago's own identity. Santiago needed this fish to prove he was the great man he once was and not simply a joke as he was to the other fishermen. Santiago also wanted to honour the great fish by catching it himself rather than someone who did not appreciate it.