I don't think it's doomed to fall, and neither is humanity. There might be some serious powershifts in the future, maybe even revolts and revolutions, but no cataclysmic collapse of society. Civilisation has spread too far, especially its knowledge, so a complete cultural change as with the "fall" of the Western Roman Empire is highly unlikely if not for something unforeseeable like an asteroid or something.
Society is so large and connected by now that I think it can adapt to most changes without radically changing the basic principles of life like it happened in the Late Antiquities. The aforementioned spread of knowledge, the decentralisation of it will prevent that something like the destructions of the Library of Baghdad or Alexandria could have a comparably cataclysmic contempary event. Too much redundancy.
As I said, there could be social unrest, though. With growing tensions between the political leanings and cultural clashes between West and Middle East there could be some significant social change, but I don't think it would result in an actual "fall".
For a full collapse too many factors would have to come together: Massive pressure in society building up and some heavy restrictions to quality of life, like heavy cataclysmic climate change or massive crop failures.
In a way this happened in Syria: They had crop failures, resulting in rising tensions against the regime and finally the civil war that paved the way for radical groups to take hold.
But it doesn't have to happen, and personally I'm quite optimistic that civilisation will continue for quite a while. I'm still hopeful that some of the dark horse fusion power concepts might actually hold up and result in solving the energy problem.
But maybe the western world will collapse into civil wars, who knows. Maybe there'll be dystopian regimes of many kinds in the near future, maybe the Singularity happens and we'll be either obsolete or thrown into infinite prosperity.
I just don't think a collapse is inevitable.
.