Too many variables to say how long bearing will last.
I would add to other issues is a 2500 lb trailer is small and has small diameter tires/wheels = high rpm tire speed at 60-65 mph vs 16"/17.5" much taller tires.
All my single axle trailers were harder on bearings than multi axle trailers were. Brakes can boil the hubs so a 2500 tandem axle has more brakes making for a cooler hub. Then speed and driving style and how aggressive are the brakes set up can overheat hubs. And taller tires roll ride easier over those cracks/potholes/RR crossing/etc.
