ChatGPT 3.5 is the base level people expect LLMs to be, it would be 2-3 generation(3-4 years) of hardware before we can reach that. Anything below is just going to get bad reviews
If I can run 100B+ models on my high-end desktop in 3-4 years I will be very happy.
I expect we'll see more unified memory designs like Apple's 128GB M1 Ultra.