You tested your lube in about the worst conditions that the lube is well known for being a poor choice for, "simple" wax, frequent rain. I think the property of a waxed chain that you missed anticipating is that wax is a solid and when the "action" of a chain flakes off the wax (you stated as such) the wax won't flow back into the lost wax areas, thus water has contact with bare metal. This is a big reason why various additives are added, to reduce the flaking off and extend the life span of the lube.
Where are you located? I have found that different locals have different "best lube" dependent on the environmental conditions. Here in the eastern great lakes wet lubes are more common. When I wrenched in NC and had a number of customers who rode the coastal islands that liked wax for the less sand sticking nature. Of course their various fasteners showed rust soon too, what with the salt
Andy