Forecasts don't move the market.

Buy and sell orders move the market.

Each transaction swaps risk for reward between 2 parties.

Are humans going to stop transacting with each other ? No.

Haven't we been using computers to conduct the transactions for decades now ? Yes.

So, what fundamental property of the markets has AI changed ?

I see more market participants.

I see the same groups of winners and losers.

The dedicated professionals versus the tourists, and this is true for any industry.

The weapons have changed, the people haven't.

Isn’t it a good thing to remove the inefficiencies? What “opportunities” would an AI be taking from humans in this space that computer algorithms haven’t already? The companies doing the trading will do as they’ve always done and innovate, and if it’s not profitable then they’ll move their funds into another aspect of the market and the inefficiencies they were capitalizing on would open to others to use. Thus, us average investors using index funds benefit from even smaller fees (or, at least, those managing the funds benefit).

Additionally, isn’t reality best modeled by the semi-strong EMH? That is, that the market is “efficient enough” to the point that consistently getting an edge by personally managing funds, even as a professional, is less efficient than simply riding the S&P500 or an index fund of the entire US market. Personally, I was convinced of that interpretation when Buffett won the bet against Protégé Partners.