I think we got “lucky” for a while when prediction markets were a small niche interest and they provided a weird novel way of making predictions.

But once they get big enough to attract the attention of people that directly affect the outcomes they will eventually become useless because people will realize the only options are to have inside information or be willing to hand money over with inside info.

The only “fair” outcomes will be things outside human control, like betting on the weather.

That's absolutely it. Cheaters or chumps, neither of whom should be encouraged.

Or you are simply better at predicting the future than most other people.