Fronts are almost always going to wear faster on just about any (unladen/not towing) vehicle because they have to steer your truck...so are generating side pressures on the tread every time you turn, and each tread edge takes more of a beating as they have to bite into terrain enough to change the direction your 3 ton truck. Plus, they move inward and outward slightly as your CVs & control arms moved up and down through their arc on compression and rebound with IFS. Standard axle rears remain comparatively in line with the axle & vehicle and don't have to force turns.
Rotate regularly through, and all will wears similarly over time.
If you don't rotate? You'll sooner have noisy, cupped and likely especially-worn fronts.