In markets with unreliable, inconvenient, or overpriced taxi service your options before Uber were to drive yourself, have a friend drive you, use public transportation, rough it in a taxi that may or may not show up and do so 30 minutes late, or simply not go.
Since low quality was previously a barrier to using any taxi service at all, it absolutely creates demand.
It seems that what you're describing is "simply" meeting existing unfulfilled demand, not creating new demand. Creating new demand would be when you move to a part of town with poor public transport because you can now Uber.
