There is also the issue of structural complexity. Today, extending the body by another 10 feet for a couple of extra rows of seats is mostly repeating a section

There is also the issue of structural complexity. Today, extending the body by another 10 feet for a couple of extra rows of seats is mostly repeating a section that already exists. Yes, there are a lot of calculations around rebalancing and flight characteristics but the construction of the extended body is pretty straight forward. How do you create smaller and larger variants of this v-wing design? Not as modular.