[gumby]

You're not machining large surfaces like wings, windmill blades and the like, not just because it's hard to make machine tools that size but because the structure and performance of the materials depend on not being machined.

When you machine an amorphous or crystalline material like a metal alloy you aren't always simply removing material, but can be putting a specific finish on the surface for mechanical reasons. Sometimes you want to cast again for performance (or cost) reasons because machining can't get you what you want.

When you build a shape from a composite material such as fibreglass in epoxy you want the longitudinal fibres to run long distances to distribute the stresses. Machining it would defeat the purpose. They are cast.

I like these blended wing designs; I'm just pointing out that your argument is not applicable to this application.

[Gravityloss]

They are made from composites. The moulds are machined.

Airliner structures are very conservative. They still use a lot of fasteners, lowering manufacturing and structural efficiency.

There is a lot of room to improve. There is a huge space for innovation in composites. It just takes a lot of time and money to ensure the more modern methods are also durable and safe.