The title supposedly refers to the ratio in the US between young and old, perhaps with a nod to Sun Tzu’s The Art of War, “If our forces are 10 to the enemy’s one, to surround him; if five to one, to attack him”. The lyrics – “The old get old but the young get stronger, may take a week but it may take longer. They’ve got the guns, we’ve got the numbers”
According to The Guardian, one of the Doors' top ten songs, "Five to One," was based on Sun Tzu's Art of War:
Sun Tzu's book is 2500 years old. If Jim Morrison did indeed use an ancient text to promote the ways of the new generation, it would be ironic yet still quite valid. Like many of today's military and business leaders, Jim Morrison thought Sun Tzu's ideas were fresh, relevant, and useful. Whether it's 1969 or 2015, The Art of War can always light your fire.
Sun Tzu's Blog (updated often)
For readers of Sun Tzu's Art of War