it truly has everything to do with STOCK.
if you dont need more gearing, some people dont mess with it, I personally cannot stand a clutch, 35s and 4.10s.
spares. when your on a trip, and you BREAK a 4.10, theres a good chance theres a spare floating around or a junkyard... odds of finding a spare 4.10 is just way better. not ready to mess with the rear, cuz your just doing a solid axle swap, well, you build your front to match your rear, then when the rear needs messed with, you dont wanna mess with the front...
bout sums it up I think