Is it possible for an open-source AI that you run at home to become as powerful as that of chatgpt and others at that level?

What would need to be true for someone to be able to run something that powerful entirely from home? Do they just need the correct weights? Assume that they don't need to do training (maybe some tech enthusiast does the training and just hands off the built model to people). Would storage space be a constraint? How much storage would they need? And how much RAM would they need? This is all for 1 person using it, not like the person would be serving an AI service out of their garage or something