To be fair, graphics cards are improving at a much faster rate than CPUs. There is kind of a soft speed limit in silicon at about 4GHz which makes it very hard to design processors which go faster than that, so processors have kind of stagnated at about that speed (faster speeds are possible, and theoretically even up to about 15GHz (and I know that there are some commercially available parts running at higher speeds), but it quickly gets less reliable and less efficient). There are some minor improvements on optimizing the architecture and do more with each clock cycle, but this generally leads to more minor increases in performance.

Unlike CPUs, graphics cards are still rapidly increasing in performance. The main difference between them is that CPUs generally have to process only a handful of programs at the same time, and is thus mostly limited by the speed of its cores. Adding more cores to a CPU has no effect once the amount of cores outnumber the amount of tasks. A GPU on the other hand often has to process millions of pixels which are calculated almost independent of each other. So there you can more easily increase performance by adding more cores, rather than having to increase the clock speed of them, staying away from that 4GHz soft limit. The RTX 2080 TI has 4352 shading units (main 'cores'), or including including tensor and RT cores it even has over 5000 cores total. CPUs on the other hand typically have between 4 and 8 cores currently.

By the way, in pure number-crunching power, GPUs can easily outperform CPUs, expecially when looking at performance per dollar. For that reason complex computer simulations are quite regularly done on GPUs rather than on CPUs.