Yes, but solar cells are in the end very simple products made of very simple resources, with a limited task: concerting one type of energy into another. That said, there is still research in making them more efficient and cheaper, and the that research isn’t cheap.
But generative AI / LLM takes an insane amount of resources to train and maintain, is complex to create, with a very complex task, and a slight increase in quality takes progressively more resources (like, say 10% better would be 50% more energy use - I don’t have the numbers anymore but iirc they were even worse). A better LLM would therefore be much, much more expensive while people are apparently already underwhelmed with the latest models. With the growing competition, fast rising costs and meagre quality updates, while already unable to financially sustain themselves right now, I truly don’t see it. Honestly, this is why I think Microsoft is cramming their subpar Copilot into everything - to sort of justify all the money they pumped into this.