As one who learned to fly in the "rubber-driven escapement era" I say "what difference does it make"?

They work well, and they're not visible (Unless you take the wing off and look down the tail). If that's what the MFG send, that's what I install. I see no reason to change them.

Of course, if they supplied some really soft balsa that bends too easily, then you could replace them with CF or a 5/16" wooden dowel