Maybe part of the price saving is in the focusing mounts. These had always been hand-lapped, which is obviously labour-intensive and time-consuming but makes for tremendous durability. When I was at the factory in May, though, they said they had some ideas on mechanizing this. If they have succeeded in doing so, this might put a good-sized dent in the price.

So do all-spherical elements (Leica's larger aspheric surfaces are ground, not hybrid, though the smallest aspheric elements are moulded glass), together with significant reductions in size and weight thanks to the lower maximum speeds. For a given level of engineering quality and complexity, the cost per pound (or gram, or whatever) is far more constant than seems intuitively likely.