Console refreshes are not as much dictated by HW improvements as by marketing strategy. With high release rate, people can as well just buy PC. People buy Consoles, because they guarantee that there will be new content for years. Moment that's no longer case, consoles will lose their appeal. As for performance and features... We can expect nVidia to push 20B+ transistors on 7nm EUV. Maybe 28B? No console can compete with that anyway due to price constraints.