Well this was explained at the first TDR rally that I attended, at the Cummins plant in 2013.
The explanation was that the engine has had the oil filter in this location since it was introduced on the Dodge trucks in the 1980's.This location of the filter had not been an issue until the new frame redesign, for the 2013.5MY 3500 series trucks with the 2500 being introduced in 2014 time frame. Cummins informed the design team for Ram that this frame redesign was blocking the service location of the oil filter removal. Ram stated that this was considered, but the frame cross member was required to allow for increase in towing capacity of the new trucks. The design team did consider this but with the demand for heavier towing capacity, the frame had to be beefed up. They also stated the the filter could be removed from the passenger side wheel well. Which is similar to the 2007.5 and up truck for the fuel filter on the driver side trucks removal, until they redesigned the fuel filter access point around 2010.
Just stating that Ram and Cummins did look at this issue, but sometimes service has to take a back seat to structural integrity of the truck frame.