"This is the same with the environment only in this case I suspect that mostly the people on the other side of the equation are future generation who get a damaged planet but none of the instant pay-off from our wastage."
The people on the other side are indeed the future geenrations. Just that right now, it seems that they will be getting a dysfunctional economy instead.
Essentially when making a cost-benefit analysis you need to have a shared understanding of what constitutes costs and benefits.
In the case of slavery the justification puts the costs and benefits on the side of the enslavers, little cost and huge benefit. If you look at the side of the slaves there is the opposite huges cost and no benefit.
This is the same with the environment only in this case I suspect that mostly the people on the other side of the equation are future generation who get a damaged planet but none of the instant pay-off from our wastage.