Good catch but I think it's very unlikely Navi 31 won't catch up to 4090. Doubling the core count with a smarter IF cache and much larger memory bus and more memory bandwidth.
If anything, they won't be able to compete in Ray Tracing. I will say that December is also very late with a November announcement.
PC Specs: CPU: 7800X3D || GPU: Strix 4090 || RAM: 32GB DDR5 6000 || Main SSD: WD 2TB SN850