I was once talking to an 'oil technician' who tried to convince me that modern oils are the Bees-Knees, and that instead of being just the product of the Catalytic Cracker, are now a sophisticated blend of compounds. He tried to assure me that this was the reason why engines now have such a long life.
However the Japanese (Honda) started using some very special alloys for their pistons and castings in the 1970s, instead of the almost pure aluminium used by British engineers. This resulted in very much shorter running-in periods. (50 miles as opposed to 500 miles.)
I don't know how much Plain Big-End bearing material has altered, but suspect it is probably slightly better now.
All other components in an engine are either caged Roller-Bearings, or Case hardened Nitrided Steel, for the crankshaft, camshafts etc. Same as could have been used in the 1930s.