I understand about UVW mapping, and for myself wish they never added the W component.
Trimble is making Sketchup to be many things to many people, it is a modelling package for art works, architecture, scientific applications, gaming, etc. It's main feature is that it is easy to use, and bolting on features for specific applications breaks just adds complexity. Additionally it is free for non-commercial use, and that helps drives sales because people get familiar with the package at home then bring it to the office.
I've written my own scripts for texture mapping and I'm sure there are better ones out there.
I'm trying a potential solution to texture mapping, and that is export the model to Paint 3D and allow Paint 3D to do the texture mapping. I don't know how Paint 3D does it mapping magic yet, as I haven't examined its output.
I've created a glTF exporter to get a sketchup model into Paint 3D, I'm just waiting for approval to be a developer before posting it to the extension warehouse. Next project will be a glTF importer, which will be a lot harder!
But again, that defeats the purpose, we want Sketchup to do everything! And remain easy to learn, fast, free...