I dont know about LLMs specifically, but its happened with other AI tech. Like those amazon grocery stores where they wanted to make an AI that just sees what items you take and bills you for them without you having to go through a checkout line, but ended up having to cancel the idea after the AI didnt actually work the vast majority of the time and they just had hired a bunch of people in India to look at camera footage and identify what people had bought instead for those purchases. I would not be surprised if some AI startup or another wasnt just exploiting the desperation of people on MTurk or whatever to get something done and just pretending to have groundbreaking AI tech doing it to fool investors.