Taking a knee to lock in an American football victory used to be considered unsportsmanlike, but then the https://en.wikipedia.org/wiki/Miracle_at_the_Meadowlands happened, where the Giants were up 17-12 with 30 seconds left and played normally. They fumbled the ball, the Eagles recovered it and scored a touchdown, the Giants' offensive coordinator was summarily fired and never worked in the NFL again, and ever since, dropping to your knee when it ensures your win is standard, accepted, and even sometimes called the Victory Formation.

There is still the remote possibility of a fumble or tackling the ball away from the defence in those cases. In the underarm bowling incident it was made physically impossible to win. In baseball terms, he had to hit a home run with the ball on the ground.

(Though as a non-American, I am indeed mystified why the kneel is legal and not regarded as delay of game!)

Or intentionally walking a batter so you so t have to pitch to them in baseball

Plenty of sports do have rules to prevent stalling tactics (either for sportsmanlike reasons or to make the viewing experience more engaging): the two-minute warning in American football, the shot clock in basketball, icing rules in hockey, etc.