You are arguing the for the theory which does in fact dictate the order of many species. Conversely you are agreeing with the theories order when you attempt to defend it. Ring species have a key problem in their definition as it implies the whole ring is one species even when not all individuals in the species could interbreed with neighboring populations at all. If you choose to think of the ring species as the population then the problem comes from the fact that it can interbreed with neighboring populations. There is no observation when the very definition of what is presumably a species doesn't even fit the definition of a species.