I agree that maintaining a single, easily recognizable identity as a small business is critical. Within the context of a very focused identity, a small business can help itself to grow by diversifying its services and product offerings.
For instance, a taxi service can offer party taxis or time period services where a car and driver might be hired for two hours, three hours, etc.
A coffee shop can add sandwiches and soup without compromising its identity, though adding pizza or Chinese food would clearly compromise its identity.
be sincere and honest.