Maybe we should go into this from the back end and define 'failure'.
The ultimate failure is ceasing to be, i.e., death. It's not an indication of anyone's failure in life, it's an indication that the vital organs have given up the struggle.
Start from that point and you get a wonderful:perspective. All life is success of a kind, whether it's in a miserable existence or as a high-flying whizz-kid, tycoon or whatever.
You've cheated death, despite the odds. You might even have courted death, in abseiling from Staffa in the Orkneys, in mountain biking around a disused quarry or around the chalk cliffs of Beachy Head. You might have been in the Forces, in Afghanistan - my cousin's son Henry* in the Royal Signals has been there, on three tours of duty and lived to tell the tale and now he's started a career in diplomatic communications. Is that a measure of success in face of the odds? His marriage - to someone else in the Forces - broke down under the strain of separation. They're both still in the land of the living, they've both seen action and got out in one piece.
In a positive frame of mind the future's rosy. That's success. Negatively, well, look at the possibles - there are enough variants to 'play about with'..
* Name changed to preserve privacy.