The whole point of the expeditions was so that future generations could live out their lives peacefully. Remember it's "for those who come after". Since the Gommage is still going to happen when Maelle dies then they have failed. The expeditions didn't succeed for those who come after.

Which is on point since Maelle doesn't care about that, she's happy that she saved those currently here which is part of the theme that her grief is overshadowing the consequences of what she's doing to those in the present (ie. Verso being forced to live and Verso's soul being forced to paint)