So from everyone's experience is 6000km pretty much the expected life span of the OEM CEATs?
I wouldn't count on that.
Tire wear depends on a bunch of factors, like how heavily the bike is loaded, by different sized riders or the loads they carry, how carefully tire pressures are maintained, how heavy on the brakes one rider is compared to the next, what kinds of roads one is riding on, whether the suspension is all properly aligned, how fast one likes to accelerate from a stop and probably some more I haven't thought about here.
You might get more, or less mileage, depending on all those factors.
I generally have run tires just to the wear bars for decades, unless they were near there before setting off on a multi week tour, when I would change them a bit early to avoid doing a change while on a trip.