It's not so much a case of botching, just having every possible file that may be required in a single package. In the case of Nvidia's, GeForce Experience and PhysX take up a large chunk (over 200 MB apiece), but when you dig into the main driver folder itself, one can see where the key bytes are allocated. The largest library by far is nvoptix at over 80 MB in size - it's for their ray tracing Optix API. Other large files include nvrtum64, nvlddmkm, and nvcompiler64 - the final two are the critical ones, as nvlddmkm is the actual display driver and nvcompiler is the library for converting shader code. Combined, they take up less than 50 MB of space; not very much in the grand scheme of things.
As handy as it is to have every possible thing one might need in a single download package, it would be nice if Nvidia offered a service where one could select aspects that aren't required, such as ShadowPlay or Nview, to streamline the download somewhat. But then this would get very tricky for the likes of PhysX, where the folder contains multiple versions of the various libraries, as required because games are developed on one specific version.
