In a flight that long that you arent that far into, landing early for a diversion requires dumping fuel (for up to an hour on larger aircraft) or risking the lives of the other passengers because the plane is over maximum landing weight.

So it very much is a case by case analysis of balancing the urgency for one passenger with the damage to the environment (dumped fuel) + risk to other passengers for a heavy landing + risks to other passengers from imposing a delay (e.g. Another passenger flying to a surgery).