Does the default really matter in this case, though? It's not even like it takes a registry hack to move it back to the left. It's right there in the taskbar settings.
You know what does take a registry hack though? Moving the taskbar to the left, or right[0]. As the screens have much more space horizontally than vertically, it would make sense, at least for some people, right? Well no, according to Microsoft.
Multiply a quarter billion children having to fix it for a quarter billion grandparents, and that's a lot of wasted time and added frustration to the world for little to no reason.