Most people aren’t super involved with AI, and basically use it passively. In the same vien, up until fairly recently, social media was generally seen as a good thing because people enjoyed it and it wasn’t common knowledge (not that evidence didn’t exist) all the negative impacts it had. That not to say social media, or generative AI shouldn’t exist, but the topic is more complex, and most people don’t engage with that complexity.

surely they wouldnt have invested trillons on it if it was garbage

Investors throw money at stupid stuff all the time. Tech in particular tends to be volitile and speculative. I mean, right before AI, it was NFTs, and before that, “the metaverse”, and befors that blockchain. All of these were said to be gigantic new technologies that would revolutionize every industry and every aspect of life, and each had billions (trillions?) of dollars invested in them. Each of them lasted about a year before their value collapsed and they were realized to be overpriced dead-ends and empty marketing.