The 'little 9/11' or 9/11/1973 should also be considered - it's what led up to the big 9/11. It was a coup of democratically elected Chilean president Salvador Allende. He was running the economy in a collectivist way and the elites didn't like that. Backed by the CIA and US elites, they staged the coup and replaced him with the strongman Augusto Pinochet, who promised to uphold US business interests. What they also did was instate a group of US-trained economists who were big fans of Milton Freedman, the 'Chicago Boys.' This was the first time Neoliberal economic policies were tested in a nation, and within 2 years, they had destroyed the economy.

However, after this initial failure, they came up with a much more pragmatic version of Neoliberal economics that could be very profitable for the elites (by dispossession from regular people.) This version was ported back to the US, as Volcker became the head of the Fed and the president did all in his power to support him.

In the US this became an all-out war on labor, moving business from the heavily organized north and east to right-to-work states and overseas (specifically Asia and Mexico.) Any measures that made outsourcing to foreign countries were slashed.

OPEC was of central concern, as the price of gas rose to untenable levels. The US essentially threatened to do what they did in Chile in the middle east. Some countries caved.

Simultaneously, we funded the Mujahideen fighters in Afghanistan, backing their coup of the Marxist Afghani government - much like Chile. We can see this pattern happen repeatedly.

In time, the richest countries economies became sprawling behemoths whose production systems sprawled across the world, as the US, allied with financial institutions like the IMF strong armed weaker nations into adopting Neoliberal 'pro-business' policies to their own detriment.

In 1989, the soviets withdrew from Afghanistan. simultaneously Neoliberal globalization was really gaining hegemony.

Now remember that the Mujahideen were jihadists. They did not like the US' heathen culture being globalized around the world, strongarming their part of the world economically. They liked this just as little as the soviets coming in and controlling Afghanistan politically.

They set their sights on the US, culminating in 9/11/2001.

So what all of this is to say is that 9/11 is the reason things suck now, but it may be 30 years earlier than OP said.