Is there a problem defining a View using a path alias? Or did I just miss something?
It could be, that I'm still having difficulties understanding your question, but I have no idea why you would expect that to work?

/path/to/%term contains an argument, and as such there is essentially an infinite number of variations that could "fit" into that path.
A path alias "/pageone" to "/path/to/aterm", does not match "/path/to/otherterm", nor any other path in the system.

Each path alias must point to a specific path, and there is to my knowledge no way to automatically "Create all possible path-aliases to for a path /path/with/%arg". There is a feature request for such a tool though.