I’m not sure I understand how Jeopardy was conceived out of the above-described scandal and to prevent it from happening again.

You win at the game by knowing what to say for each prompt in order to get points. What is a “question” or an “answer” is just semantics. In other words, a contestant could conspire with the gameshow to cheat at Jeopardy the exact same way Van Dorne cheated at Twenty One, by getting the correct “answers” on notes before the game.