YOu want enough wiggle room to wiggle out of the theory.
You can't just look at Xers. If anything, the previous 4T and 1T were too short for the cycle as a whole. If the saeculum and generation lengths stay the same, then events have adjusted, with the result that the 3T this cycle was longer: 1984-2008. Sometimes events (and the planets btw) shift the timing of turnings a bit, but the overall cycle stays at 80-plus years.
Polls I have seen (including here) say that 2008 seriously affected most people, but 9-11 very few. 9-11 was a spectacular disaster, and some people here are hypnotized by that to think it was the catalyst for a 4T. Other than it being a big event, there is no basis for that idea.
Rallying around a president has nothing to do with a 4T. There was simply no commitment to the wars, by Bush or by the people, and they had nothing to do with a threat to the United States. It was simply business as usual.
Says who? They knocked Boomers constantly, as most people here do.
Internal division is indeed a primary feature of this 4T, but the main focus of that division now is whether the government should deal with social, economic and environmental problems or not. The culture and foreign policy divides are still there too, but they are not the main issue right now. The culture wars dominated the 3T (which was given that title), and the foreign policy divide dominated the 2T. The divide itself must be dealt with later in this 4T, and will be decided somehow in the mid-2020s.
If internal division is a primary feature of the 4T, as you say, then it follows that a foreign policy challenge like 9-11 cannot be the catalyst for it.
No, it just proves Xers are more right-wing. They are the Tea Party crowd that took over in 2010. They may be shoved right back out of office again, and that
will happen if the people decide to have any sense at all. Liberal Boomers like Grayson will come right back in. And maybe some liberal Xers too.