When I was young a zillion years ago I visited the Smithsonian's Air and Space museum, and admired what I think must have been a mercury capsule. Upon peering through the window, what struck me first was the construction. Thick plates of aluminum, large electrical components, etc. These were the materials and components of the era.
Fast forward to this comment speculating about the BFR's capability of putting an Apollo stack on its way to the Moon (it seems not to be possible).
I'm wondering, roughly, hypothetically, if one wanted to build a working replica of an Apollo Moon landing mission from current aerospace materials being used in spacecraft and land on the Moon with a crew as a sort of homage, how much lighter would it be?
One third lighter maybe? Could it be half the weight?
Would modern engines, electronics, or electromechanics (motors, pumps, etc) help a lot, or would it be mostly structural weight?