What keeps most old school 4x4s in 2wd is the transfer case.
You're told not to drive them on paved surfaces or binding/damage/poor steering will happen.
In recent years Ram1500s with the big horn and upper trim levels have a 4x4 auto position.
This you can, and should drive on paved roads, helpful when it rains, snows,ice, etc. like having an AWD vehicle.
Without this feature, most Ram owners will never use their 4x4, as a 4x4!
Wish it was offered on 2500 and 3500 Rams!