I think a lot of the service is variable based on the crew - I think those aprons, etc. are things that UA phased out long ago but some crews (especially HNL based ones) have extra touches that make the flight special - i.e. one decorated the service carts in F on a HNL-SFO trip.

I agree there are some low cost things UA can do to make the Hawaii flights more special... but honestly for most pax, it's the destination, not the flight.