The Traffic on OGG is Coming From Somewhere
I don't know why CO is reducing service to OGG. Hotels are often booked to maximum occupancy, the roads are always congested with traffic, and the once quiet and quick ride from OGG to the resorts at Kannapali is frequently gridlocked --so bad that on my last trip there, traffic was backed up to the tunnel prior to getting into Lahaina!
And there's definitely a ton of air traffic at OGG --the security lines seem to wrap around endlessly out front.
So while those passengers may not be flying CO, they're flying someone into the island somehow. Maybe CO wasn't competitive enough on the pricing (or the timing/frequency of the flights) to be successful there.