Because I don't think that the cultural imperatives that lead to good service are related to tipping at all. Plenty of countries in which tipping is not the norm offer good service as the norm. The prime example is New Zealand. Another example is Iceland, as in its way is Turkey.
And let's not forget Japan, where I've had better restaurant service than anywhere in the world, and where if the bill was Y3,815, I paid Y3,815.