Starting with a net worth of $0, it shows you how long you have to work till your money will make you enough money to live on forever.
Make $1,000,000/yr, and live with a lifestyle cost of $950,000/yr? A 5% savings ratio. You will have to work 66 years till your investments will support your lifestyle.
Make $40,000/yr with a lifestyle cost of $15,000/yr? A 65% savings ratio. You only have 10 years of work ahead of you till you're financially free.
What gets you to financial freedom is the amount money you save and its relationship to your spending.