We are descending into a dark age. We have a culture of death, where we've replaced reproduction with immigration. This has been true for decades, and is becoming more pronounced with the passage of time. We have too many elderly, and our women are facing ever increasing pressure to choose service over family, creating a spiral effect. We will reach a point where we don't have the numbers to keep the infrastructure going. Our modern technological society relies on myriad resources being available, and as those resources become unavailable, all the knowledge in the world won't matter. Once we're unable to implement our discoveries and designs, people will forget them.
As we became more advanced, our creations became more delicate. The more delicate they are, the quicker archeological evidence of them deteriorates. There is no reason to believe this hasn't happened before.
ISIS are standing in opposition to this pattern, but I doubt they will be effective enough to prevent it. I'd say a dark age is pretty much guaranteed.