“…neither can accept that this is the end, much less look forward beyond that end.”
You must have a very curious definition of “the end” in mind, if you can simply look past it.
“Because the truth is that we are all grieving already, whether we know it or not.”
Grieving? I know you’ve noticed that maybe the human race hasn’t exactly been the best thing that ever happened to the broader ecosystem (call it Gaia). Even if one accepts your “doomed society” narrative, for anyone who sees a broader, not so anthropocentric perspective, maybe grief is not so appropriate; maybe relief instead? Maybe the cycle of life, death, and rebirth applies even to societies not just individuals? Maybe that is something to be celebrated, not feared or grieved over? Maybe that has something to do with being able to “look forward beyond that end” that you mention earlier?