If you look at Blend2D (a CPU rasterizer), they seem to outperform every other rasterizer including GPU-based ones - according to their own benchmarks at least
And please keep in mind that Blend2D is not really in development anymore - it has no funding so the project is basically done.
That's such a shame. Thanks a lot for Blend2D! I wish companies were less greedy and would fund amazing projects like yours. Unfortunately, I do think that everyone is a bit obsessed with GPUs nowadays. For 2D rendering the CPU is great, especially if you want predictable results and avoid having to deal with the countless driver bugs that plague every GPU vendor.