I have still been researching into this matter and I found two dates,
Adventurer trainers, the cosigners and pawnbrokers were removed on
Sept 18 2007
Crafting Trainers, Vault Keepers and Stewards were removed
June 30 2008
but I can't find specifically when the resources themselves were removed. I can only assume it is the second date as that is when the head(s) of the island(s) left. Support dosen't know either, so unless someone has a better date, that is it. Coincidentally, it fits nicely
The Battle of Lerena/Grayling was May 25 2008. This was the day Blight anchors spawned in a community area. Perhaps the population of these islands were so low, the residents feared that in the case of an invasion, the Gifted could not be rallied as quickly as was Lerena, an island that constantly has gifted running up and down it for ROPs.
Another scenario could be that as there is no records of what happened to the resources, perhaps they dried up slowly over time.
With no resources and no visitors, you really don't have a village, especially as the islands are so remote.
I'm trying to find an example of a thriving Istarian settlement that meets those standards, (remote+no resources) to perhaps disband this second theory, but I'm not finding one. It could entirely be a possibility of both theories. With no resources, you cannot make weapons or reinforced buildings. I also notice that in the patchnotes for June, this was a round of plot resizing, so most gifted stayed close to home.
At any rate the Stewards are gone. With no way to actually question them, perhaps all we gifted have are theories. Perhaps Pratt may know what happened to the others, but good luck questioning that rude naka.