This entailed most urban centers in the Eastern mediterranean (besides Egypt and Mesopotamia) being violently destroyed, and writing completely disappearing in large regions. And all this happening over the course of maybe 50-100 years.

Arguments can be made for the declining Western Roman Empire, and collapse of some of the Chinese dynastic states. But as you point out, one can rather easily counter argue that this wasn't collapse of civilization but rather the collapse of a specific hegemonic state and its replacement by several smaller competing powers. Civilization still remained: urban center and writing didn't disappear. These were collapses of states not of civilization.

Literate secular class, including Roman state bureaucracy, disappeared as well, and with it large scale planning, monetary economy, large construction projects or most of long distance trade. Only the Church still maintained reading and writing, but that was a very small group of people.

All of this may not fulfill your definition of collapse of civilization, but I believe that a Roman citizen of 2nd century AD, suddenly transported to the 8th century, would be aghast seeing what became of his former home. Even cattle shrunk to half its former size and crop yields diminished, as agricultural best practices were forgotten.

I love to point out how the symbolism of many modern governments is the result of a sort of cargo cult of Roman Republican culture. Government buildings to this day copy the dull gray ruins of Roman buildings, just as many 18th/19th century governments declared popular authority from a Latin-imitating "Senate", filled to the brim with Roman symbolism.

With that in mind, it's not surprising that many today believe the 18th/19th century's "fall of Rome" and "barbarian invasion" myths as a sort of predictive weak-spot of modernity. If you view civilization as a linear path, a story of how the intrinsically superior empires of the Greek/Macedonians and Romans successively lifted the world out of its natural, primitive barbarian state, and the shifting power centers of the 3rd-8th century as a "turning back of time to the Dark Ages" or linear regression along the same path, then the "collapse" narrative is as plain as day. This view on history is pure fantasy, of course, which is why the collapse narratives set in modern days seem so fantastic as well.

> The West _is_ going through a lot of change/political soul searching right now

I believe that you're understating the situation a bit - at least, here in the United States, we're beginning to see markers of the kind of "cultural revolution" that happened in Russia in the 1910's and China in the 1960's - and while neither of those states have collapsed, exactly, tens of millions of innocent people were killed and rather unpleasant governments installed as a result.

While categorically different from total civilization collapse, I don't blame my fellow Americans for starting to get nervous and start prepping like a high-school senior.

If that's what you legitimately think of the developing world, then no wonder you believe in collapse so strongly (almost like the inverse of the "noble savage"; a fear of letting go of the "Western enlightenment" even if it comes from critics of modern Western regimes). Please, go outside and experience the world. Life has fundamentally changed for most of humanity, except for the occasional isolated remote community, over the last 50 years. I urge you to define what "peak prosperity" is and how developing nations lack it before we discuss what "collapse" is and the loss of "peak prosperity".

I have lots of family in developing nations and their lives have absolutely, fundamentally changed. It's borderline insulting to imply that developing nations still live like they did in the past.

Prosperity is always relative to the system you're immersed in and in a globalist world, your prosperity is defined by the prosperity of how people on the other side of the world live. Americans can believe they have the best living conditions in the world and same can do northern Europeans and maybe Japanese too. Let's throw in urbanized chinese middle class too. But in developing countries they don't have the privilege to believe they are in that competition. They are always a province of the empire and living in scarcity.

This says nothing about the enormous changes that went on pretty much everywhere in the rural parts of every country with very few, isolated exceptions.

I expect that, much like every other community, the loudest “collapsers” are merely an embarrassing minority, and certainly I hear that the people who stockpile food and maintain a strong relationship with their neighbours roll their eyes at those who stockpile ammunition and do nothing else.

If the same happened to New York, with the subway abandoned, whole neighbourhoods overgrown by poison ivy and the skyscrapers collapsing from lack of maintenance, "post-apocalyptic" would probably be a fitting word.

I am not sure how you can call such a massive loss of complexity and population something else than a collapse.

It’s the timescale that makes it. I’m thinking Methyr Tydfel in the UK as a point of reference for similar fractional change in the first roughly century of decline, but peaking in the Industrial Age.

If this happened in NYC, I’d expect (say) Queens to turn to rubble while (say) Manhattan is getting freshly built skyscrapers. Plucky adventurers with assault rifles and bows looting tinned food from a suddenly abandoned Whole Foods is more of what I expect during hurricanes than as a standard result everywhere all at one.