Surely the majority of people who have ever stood for election have lost. That’s the nature of the concept. In a Westminster parliamentary election, for instance, many candidates who appear on the ballot paper of any given constituency would have already taken part in at least one selection process just to arrive at that point. They would have left a string of ‘losers’ in their own wake in doing so. Despite its faults (e.g. the single-largest-wins voting system) a Westminster election, whether it be general or by, still carries an element of the fun of the fair about it and participants often speak of their sense of honour or privilege simply for having been able to take part in one.
Real losers would perhaps be those who, despite having all the trappings of wealth and/or power and with all the benefits of education, contacts, networks, doors opening, deference, influences and sundry other opportunities etc, then somehow manage to contrive to lose it all. Obvious examples of this would be monarchs who fell as a result of revolutions such as Russia’s Nicholas II, France’s Louis XVI and England’s Charles I. Then there are those who were defeated in battle and subsequently fell from grace such a Darius III of Persia, Moctezuma II of the Aztecs and Atahualpa of the Incas. Away from statecraft then history is littered with those who made a fortune (or inherited a fortune) but then frittered it away ending their lives in relative or even abject poverty, a famous 20th century example being Woolworth heiress Barbara Hutton. Each case, of course, has its own nuances and each depends upon a greater or lesser extent on such variables as character defects, being overly optimistic, being overly pessimistic, taking ill advice, making poor judgements and, of course, sheer bad luck.