So from the start, I had a low impression of the rest of the book, when on the first page of the preface, he writes, "In March of 2002 the United States invaded Iraq with massive force only to be surprised by the swiftness of the Iraqi military collapse."... Only problem with this, is that the second paragraph of the first page of his book gets the year of the Iraq invasion completely wrong... which then got me questioning the integrity of his statements from the beginning.
That being said, while Schwartz raises some interesting points, similar to a good deal of scenario planning work, the conclusions are rather obvious and the thought process not particularly deep. To his credit, he does recognize this element of scenario planning, and addresses it by saying that governments and business leaders often think these thoughts, but do not string them together into plausible scenarios.
Recognizing that the book was written in the early days of the so-called "War on Terror", he pays a disproportionate amount of time to discussing 9/11, al-Qaeda, terrorism, radical Islamists, etc. So much so however, I would say it weakens his overall arguments and dilutes his main theses (and is frankly just annoying when he makes surprisingly ignorant essentializing statements on the Islamic/Arab world).
Long story short, despite the slogan of his book, the scenarios contained within it will neither "change your world and your business," they will simply make you wish for a few hours of your time back.