Luger has fewer parts than a P38
NOTE a correction, to a mistaken statement above ...
The Luger actually has fewer parts ( about 16 fewer ) than the P38.
parts count : Luger = about 40
P38 = about 56
The Luger is also SIMPLER, to understand and field strip, all the way down to the firing pin, with NO TOOLS. You can see the entire action ( it's more linear ) of a Luger easily, ..... but the rotating parts and processes going on inside the frame of the P38 are actually more complicated.
But yes, the Luger is more complicated and costly to make, the price for that increased functional simplicity.