There might be a good reason for this. Raster effects were already really good in newer games, and ray tracing could only improve on that high bar. It’s filling in details that are barely noticeable, but creap ever so slightly closer to photorealism.
Old games start from a low bar, so ray tracing has dramatic improvement.
I think part of the push is just from Nvidia to try and get vendor lock-in, like they have with CUDA. Many games that use raytracing will only work on “RTX” cards which are only sold by Nvidia. Raytracing also has the benefit of increasing demand for upscaling, like DLSS, which further increases vendor lock-in.
Also, most devs are going to be using some sort of game engine where the hard parts of rasterization are already taken care of, like with Lumen in Unreal Engine 5.