Keep in mind that with the 2080, they added raytracing acceleration and tensor cores. Both add area and improve performance of specific user cases, but my guess is that they don't show up in that TFlops number.
This is it - you can't just compare FP32 TFLOPS. The newer cards have a ton of extra precisions, custom cores for certain workloads, and on chip memory, all of which use silicon area and transistors, but none of which boost the FP32 TFLOPS metric.
I could design you a chip that is nothing but FP32 multipliers and adders that has, theoretically, a ridiculous TFLOPS per mm^2, but it would be next to useless in any real workload.
GTX 1080: 42.81 mm^2 per billion transistors. 41.53 mm^2 per TFLOP. 0.97 billion transistors per TFLOP.
RTX 3080: 15.55 mm^2 per billion transistors. 33.17 mm^2 per TFLOP. 2.13 billion transistors per TFLOP.
They scale well for transistors against die size, and TFLOP against die size, but terribly in transistors per TFLOP? That can't be right.
Checking https://www.techpowerup.com/gpu-specs/geforce-rtx-3080-ti.c3... I now see it says "Based on speculation / placeholder", which makes me think it's all just totally made up, and not reliable evidence to declare the death of Moore just yet.