In any highly competitive market, where there is a surfeit of products all competing for the same proposition, then inevitably, the propositions become hard to distinguish. In these cases a sort of exclusion principle applies. Once one successful brand has occupied one slot, the next successful product to compete in that space will have to occupy a different tonal slot.
This is where brand tonality and personality becomes the difference; When price, product, promotion etc are all identical.
To understand this graphically it helps to see tone in terms of the following wheel. It shows how brands connect to the idea of archetype, an idea originally conceived by Jung.
If you’d like to read more about the role of archetypes in brands and organisations try The Hero and the Outlaw, by Margaret Mark and Carol S Pearson.