The madness of SkinnedMeshRenderers and SharedMeshes/materials

So, Trying to create a new skinned mesh renderer, so it can use the same settings as imported, but with say different vertex colors or vertex placements has been very frustrating to say the least. I got it done, but it requires a whole bunch of workarounds.

I thought this must be because of performance, shared meshes more performant than a bunch of individual mehses with different vertices, normals, colors, etc.

Turns out, that is not the case, at least not for me, as I eventually was able to get new instances of skinnedMeshRenderers with changed meshes and vertex colors, and saw zero performance difference.

What I don't get is why instead of this:

Code (csharp):

1.  
2.             Mesh mesh0 = SMR0.sharedMesh;
3.             Mesh meshInstance0 = Instantiate(mesh0);
4.             meshInstance0.colors = vertexColorStream;
5.             meshInstance0.vertices = verts;
6.             SMR0.sharedMesh = meshInstance0;
7.             SMR = SMR0;
8.  

can't it be as simple as this:

Code (csharp):

1.  
2. SkinnedMeshRenderer SMR = new SkinnedMeshRenderer(OriginalSMR);
3.  

or

Code (csharp):

1.  
2. SkinnedMeshRenderer SMR = Instantiate(OriginalSMR);
3.  

like just about every other component?
Why must everything on a skinnedMeshRenderer be shared and almost inaccessible to a new instance of it?