Multiple times. The perspective I've adopted is to look at what you learned in the process of each failure and how that improved your ability to do a better job on the next venture.

The truth is that many don't have the stomach for "sticking with it," doing whatever is necessary to keep going in the down phases (I highly recommend the poem "If" by Rudyard Kipling and see if it resonates).

You only truly "fail" when you quit. If you can make the necessary sacrifices to struggle through the dark days, your chances of succeeding increase greatly. I'd argue "survivorship bias" is just an excuse made by people who give up (I know that will sting some of you, but really marinate on it).