You are mixing sci-fi level of cutting edge basic research (fusion), with commercial products (chatgpt). They are 2 very different type of proof of concepts.
And both will likely revolutionize human society. Fusion will simply commercially become a thing in 30/50 years. AI has been on the market for years now. Generative models are also few years old. They are simply becoming better and now new products can be built on top of them