That would be nice but doesn't match reality unfortunately, there are even new fixed-fuction units added from time to time (e.g. for raytracing).
Texture sampling units also seem to be critical for performance and probably won't go away for a while.
It should be possible to hide a lot of the fixed-function magic behind high level GPU instructions (e.g. for sampling a texture), but GPU vendors still don't agree about details like how the texture and sampler properties are managed on the GPU (see: https://www.gfxstrand.net/faith/blog/2022/08/descriptors-are...).
E.g. the problem isn't in the software, but the differing hardware designs, and GPU vendors don't seem to like the idea of harmonizing their GPU architectures and they're also not a fan of creating a common ISA as compatibility shim (e.g. how it is common for CPUs). Instead the 3D API, driver and highlevel shader bytecode (e.g. SPIRV) is this common interface, and that's how we landed at the current situation with all its downsides (most of the reasons are probably not even technical, but legal/strategic - patents and stuff).
