I have been a firm believer in predictions markets since first learning about them over a decade ago (still am). I certainly did not predict this would happen, nor would have I seen it as a plausible outcome had you asked me.
I donāt know of anyone else who did either, neither in the for or against camp. The counterarguments were always:
Assassination markets
Insider trading
Something something unduly influencing results of elections
I donāt remember seeing any list of counter arguments which included: āwill be optimised to prey on people with weak impulse controlā.
What are the other 3 on your Mount Rushmore?