Here are the stats for the sports with the most wins:
Athletics - 18
Formula One - 8
Tennis - 6
Football - 5
Boxing - 5
Cricket - 5
Cycling - 5
Figure skating - 3
Eventing - 2
Swimming - 2
Golf - 2
Swimming - 2
Horse racing, snooker, rugby union, show jumping, motorbike racing, rowing - all 1
I reckon athletics has a big advantage because people bloody love the Olympics, so a gold or golds in Olympic year is almost a guaranteed win. It's harder to stand out in team sports, unless you get a really standout performance like Stokes, or winning a World Cup like Wilkinson. Athletic also has by far the greatest number of second and third places.