Let's take the situation at home. The U.S. government provides no financial support to its athletes (of the 200+ countries that attend the games, we're one of three to not do so), which places the onus for athlete funding on the U.S. Olympics Committee. As a nonprofit with an estimated annual budget of $170 million, they can only afford to offer stipends and other benefits to a small number of athletes, most of whom will be competing in high-profile, recognizable sports. If you're an athlete who picked a less-marquee sport such as racewalking or dressage (basically horse dancing), then too bad. Don't let the hurdles bang your ass on the way out.
In a just world, this horse would be richer than Michael Jordan.
And it's not like they can rely on sponsorship deals or prize money, either. A recent survey found that only the top five athletes in events such as running, jumping, and discus throw were earning over $15K a year from their activities -- a figure which includes everything from sponsorship deals to prize money to, yes, the aforementioned stipends. To get a gold medal in money, in other words, you have to be at the very top of your game in a sport that people give a shit about all the goddamn time, not just twice a decade.