Is there an end to the suffering in general? Buddha said that Nirvana is an end to the suffering of an individual.
However if we think from a larger perspective, there is no end to the suffering as a whole. The world will get created again and new Buddha will or will not arise to help us escape the suffering. There were Buddhas in the past and there will be many Buddhas in the future but so has the suffering manifested in the past and will manifest in the future.

My question is: Is it possible to envisage an end to the suffering, absolutely for all, for ever?
Yes and no. To be is to suffer. Our desire to be is what keeps us on the round of rebirth. Nibbana will come to every being just not all at the same time(Vast time). That's what I've heard from various teachers. 

We mix our individual truth up with the truth of society and until we can see the difference we have no business trying to fix society as we seek while ourselves we are broken.  Our business is to fix ourselves then fix society one individual at a time. The society of the entire universe.

So, imho,  I think you should tend to the universe of mind and body, moment by moment instead of the "business as usual", blurry truth of the world.