The number is based on the assumption that you will live pass 80 years of age. The average Canadian life expectancy is 76 years of age for men and a few more years for women. If one can only live to the age of 66, one year after he retires, he only need 40,000 RRSP income. If one can only live to the age of 50, there is no need for RRSP. Therefore, you better figure out how long you are going to live
You don't need to wait till reaching 69 to start withdraw from your RRSP. 69 is the last year you can contribute to your RRSP. After, you have to transfer your RRSP into RRIP or withdraw in full.