Most understanding of the Bronze Age Collapse these days views it as a result of the complexity and necessary interconnectedness of the societies causing anything destabilizing to bring the entire thing down. For example bronze required multiple metals not all found locally to any of the powers; political and social order followed a centralized top-down hierarchy (palace economy); and agriculture by that time depended on significant division of labour and technology. When everything was disrupted and contracted to a critical degree by a series of smaller crises, some parts of society simply weren't able to sustain themselves and the cascading failures took out everything.

The contention here is that the world now has a similar vulnerability due to complex global supply chains, and that a large enough disruption would collapse everything. Many populations depend on imported food to survive, production is so distributed that many end products are impossible to produce in any kind of scale (or at all) without supply chains millions of people deep. Take away half the oil production, half the internet, half the steel and see if the other half grows it back; hell just dial up the Thanos factor and eventually you'll see what modern society's bus factor is. It's not about the white people being necessary to 'keep things in order', it's just the idea that too many of the cogs needed are in America; the same would apply to any other disruption of a similar scale.

Luckily though we have capitalism now. Economies are able to respond rationally to systemic disruption and rearrange distribution optimally. This is true now because neo-liberalism patched out the bugs in the invisible hand code that stopped individual self-interest from always magically producing net altruism.