It's cool, and there are open-source projects that can convert from STL to WebGL, so this kind of conversion is quite accessible, and e.g. GitLab could easily incorporate it as well (if they haven't already).
While I know GitHub does that (see, e.g., https://github.com/kragen/stl3dpy/blob/master/showerring.stl) I think it's lacking a lot of things to be a reasonable Thingiverse replacement. It can render STL files, but not OpenSCAD or STEP/IGES, for example, and it has no way of associating different files (even files it can't render) to a single "thing" the way Thingiverse does. From GitHub's point of view, your example is a random file that belongs to a project named "3D", and mine is a random file that belongs to a project named "stl3dpy". This poses obvious problems for implementing search.
Oh wow. Not sure how I missed that, thanks.
Considering hardware projects are just software (CAD files, schematics, diagrams, documentation) I’d love to see Github or Gitlab or someone take this on.
For what's worth, GitHub actually renders STL as a 3D representation, if you click on the file, e.g. here [1]. (Just a random example, I'm in no way affialiated with the project).
Of course, it's still lacking important features, e.g. search parameters, etc, but... it could work.
[1] https://github.com/iliterobotics/3D/blob/master/Justin/Uncom...