I guarantee you that when the technology exists to bring back some of these species via cloning or genetic engineering, they will have some habitat restored once they are ready to re-introduce them. Otherwise it would be a complete waste of time and money.
I think the comment it more about what if we have technology but no space for resurrected species?
Then we wait until we have the space. There is no deadline to meet.
Pretty sure the deadline is our extinction, but after that, the animal kingdom can flourish again
How many more species would be classified as extinct if not for zoos?