I don't think the show is rigged, but it is odd how the show suddenly has all these super-champions. I do think it's partially due to Holzhauer changing the whole paradigm of how the game is played with his 'jumping all over the board' strategy to seek out the Daily Doubles and get the high value clues first. I think if someone dials into that, they can jump ahead more quickly early on in the game, especially if they can go after the high value clues early on because they have the timing of the button down and are just more comfortable on stage than the two new contestants.
If they wanted to rig Jeopardy, they could easily do that by changing the response time of the returning champion's button to be even a fraction of a second or so faster than the other contestants. Although I I would imagine there is some sort of check for that. I heard a recent interview with Drew Carey where he was describing how they rigorously test all the games on Price is Right to assure statistical randomness. I don't know if that's some sort of law or regulation or just as a way to assure the producers/advertisers/insurers that the game is fair.
And I loved Mayim Bailik on Big Bang Theory, and she seems like a great person, but I seriously can't stand her as host. Those dramatic pauses she takes after someone provides the question to tell them that they are correct, especially after daily doubles, are so annoying. I miss Ken.