Bill Mill: I continue to not understand the economics of reviving people in the future. Your argument here seems to be that reviving frozen heads, no matter the cost, is a moral obligation. That does not make sense to me.

He isn't saying that it will happen "at any cost". Obviously, there will be a time when reviving people will be too expensive. But you're assuming that it will stay too expensive forever, even if people were, say, revived gradually during a period of two thousand years. That seems bizarre, especially considering how much money societies spend on charity, welfare and historical research even today - let alone how much they can spend in a post-Singularity future, when poverty might very well be entirely eradicated.