More slaves from the war. With any luck (not getting my hopes up), this game has a vast influx of slaves from other alliances. And they aren't happy about it, as pointed out above. Telvanni did refuse to go along with it. And perhaps Indoril does suffer economically.

I've been pretty disappointed with this game so far, but they seem to covering this part well.

Not to mention that the Real Barenziah states that the elven lifespan is one thousand years. It's pretty obvious that Beth never really defined such details, so inventing a firm answer like this causes a lot of contradiction. On the flip-side, maybe people will finally stop asking that question.