They're priced differently because international data costs more to Vanguard from the source index providers (FTSE, MSCI, etc). The two funds containing international data are priced identically at a 0.11 ER, while the one US-only fund is cheaper. I see your point about being able to mix VXUS and VTI to get a similar (but not identical) performance to VT at a slightly lower price, but that's not how the data business that drives the ERs behind the scenes works.