I do not collect K98ks, though I have had a few, mostly pre-war. Is a late WW2 K98k (other than the "last ditch" ones) in any way operationally inferior to a pre-war item? I suspect not. The aesthetics cost money/time and laminated stocks, stamped buttplates and welded front bands probably worked as well as the nicer looking, earlier parts. After all, the 1903a3 rifle is just as good as the (to me) nicer looking 1903, and it shoots well. The plants that made those rifles weren't being bombed.
I suspect the availability of manufacturing processes in WW2 that were not used or developed in WW1 had a lot to do with the abandonment of the aesthetics. It might have occurred in Germany even if the manufacturers had not been under the duress that they undoubtably experienced.