(I am kind of making the assumption that their perfect, all-powerful AI, once developed, would also be a bit more efficient than current models, allowing it to more easily run on consumer-grade hardware. Also, in the meantime, consumer-grade hardware is only getting better and more powerful.)
You can ask an LLM to vibe-code you a new model from scratch, but pre-training it you’re gonna be limited by the resources you have available
Why would you ask the uber-LLM to code you a new model that hasn't been trained yet? Just ask it to give you one that already has all the training done and the weights figured out. Ask it to give you one that's ready to go, right out of the box.