Hi
As MBDOC stated, cost!
Dismantle a 119 engine and admire what was known as "Craftsmanship" Holes were drilled then threaded, all mating surfaces milled to perfection, truly built the "Old German Way!"
Dismantle a 112 or a 113 and admire "Manufacturing" Holes that have self tapping bolts screwed in by a machine, non critical mating surfaces sealed with silicone sealer/filler, very evident that these are built the "Times a Million Way!"
I love performing mechanical surgery on MBZ's formerly crafted engines but the new generation engines do very little for me beyond maintenance/triage!
MrC