The Scions were formally disbanded so as to avoid being called upon in perpetuity by every world power to attend their myriad woes. Alphinaud even says that their operations will return to being largely conducted in secret, as they were in A Realm Reborn and previously with the Path of the Twelve, mirroring the initial move to Mor Dhona to remove themselves from spheres of political influence.

I never took this to mean that these characters were just going to evaporate from each other's lives indefinitely, just that they were going to operate independently of each other more. All the former Scions that we're regularly in contact with are close personal friends, and they come and go from their own tasks with regularity (Y'shtola and Estinien in the void camp while G'raha and Krile were investigating the Twelve, for instance). I understand that this is unfortunate news for those who loathe the Scions, but I think it's been made pretty clear from the outset that the principal cast is always going to be involved in some way.