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.
To be fair, those old games have been rewritten in newer engines in order to support ray tracing, and at that point you could apply other modern global illumination methods and get almost the same effect with less performance cost.
The thing that makes raytracing so attractive, though, is how extremely easy ray tracing is to implement. Unless I’m copy-pasting others’ finished work, I can make raytracing work over the weekend with Vulkan or DirectX shaders as opposed to having to implement 10-15 other shaders for the same effect over half a year of development.