Student or Learner
Does "threw his knapsack over the brick wall" just mean a metaphor of "abandoning something"?
In 1879 Thomas Edison announced that he would publicly display the electric lightbulb by December 31, even though all his experiments had, to that point, failed. He threw his knapsack over the brick wall―the numerous challenges that he still faced―and on the last day of that year, there was light. In 1962, when John F. Kennedy declared to the world that the United States was going to land a man on the moon by the end of the decade, some of the metals necessary for the journey had not yet been invented, and the technology required for completing the journey was not available. But he threw his―and NASA’s―knapsack over the brick wall. Though making a verbal commitment, no matter how bold and how inspiring, does not ensure that we reach our destination, it does enhance the likelihood of success.
Yes, it is metaphoric, but its meaning is opposite to what you surmised. It means that the person made a decision to embark on their quest and a commitment to achieve their goal knowing the difficult challenges ahead.