I wouldn’t even go that far. Having iron weaponry when your opponents have bronze is an advantage, yes … but I really doubt that it’s a decisive advantage. It’s not like a bronze-wielding army is suddenly going to become helpless against a foe with iron weapons. If the bronze-age army has better numbers, better tactics/strategy, and/or better motivation, they may very well defeat an iron-age enemy in battle.

A few times, sure, but on a historical scale, it’s a ticking time bomb. One of the advantages of iron, other than being significantly superior for usage in edged weapons (armor is a mixed case), is that it is much more plentiful and cheap, and doesn’t require distant supply lines to be maintained in war time in most cases.

“Their swords are better than our swords” is bad, but not necessarily spelling doom. “Their swords are better than our swords and they can make 5x as many for the same time and cost, and they aren’t reliant on their trade ships not being pirated or sunk by storms to continue making them” is a bit dire.

According to this link those first Subsaharan bloomeries were from the 6th or 7th century BC placing them well after the Bronze age from about 1000 years before. In this way it doesn’t look like they had the technological insight to skip the Bronze Age discoveries, they were just recipients of the technological advances from other parts of the world. Iron bloomeries were already in use elsewhere in the world over 1000 years before Subsaharan bloomeries.

Bronze Ages are regional; Subsaharan Africa lacked any such distinct Bronze Age in its history. Subsaharan Africa is suspected to have begun working iron and bronze effectively simultaneously in most areas, with some suggested dates as early as the 2nd millennium BCE, and a few outliers in the 3rd millennium. Furthermore, the design of bloomeries in Subsaharan Africa is largely autochthonous to the continent, without clear links to bloomery designs of North Africa or Eurasia.

The point is entirely that there were no “Bronze Age discoveries” other than bronze; the discovery of bronze defines the Bronze Age, and very few material technologies are linked to the usage of bronze, specifically. Iron has somewhat broader uses, but in most cases other metals can be substituted, in principle if not necessarily scale. The reason why so many cultures end up with a Bronze Age and an Iron Age is because bronze and iron are incredibly useful military metals, and if any of your neighbors have bronze or iron, you will learn from them very quickly, or else be very quickly conquered by their elites.

“Bronze Age” covers an incredibly wide variety of societies, as does “Iron Age” - the only unifying factor between such societies is the discovery of bronze or iron. In fact, of the two, I would regard “Bronze Age” as much more meaningful, as widespread use of bronze usually implies long-range trade routes, which in turn imply relatively robust state structures to ensure trade routes remain viable. “Iron Age” societies run the gamut from the incredibly urbanized and developed proto-industrial Roman Empire, to early nomadic Bantu tribes which rarely numbered above the low thousands.

Again, no technologies of the Bronze Age are necessary for the discovery or development of iron. If the first viable furnace in a region that is developed can reach temperatures above not just bronze, but also above the point needed to make iron bloom, there’s no need for any form of intermediate stage - and bloomeries do not require any metal tooling to be designed or constructed.

For that matter, China, for instance, is generally considered to have skipped bloomeries entirely.

Technology is not linear.

No argument to that statement. I would argue that materials science is even more underappreciated.

Materials science is the main thing most people consider when thinking about the conditions of the past, along with engineering/design, often to the exclusion of theory and organizational technology.

But the Bronze and Iron Age did not lead to one another. In fact, much of Subsaharan Africa lacks a Bronze Age entirely, precisely because they don’t lead to each other - the forms of furnaces (bloomeries) that spread in Subsaharan Africa were efficient enough to smelt iron from the start. Bronze is not needed to smelt iron - bronze or iron tools (though obviously you still need the iron itself) are not even needed to smelt high-quality steel, if you really know what you’re doing - all you would need are earthen furnaces, clay crucibles, coke (processable, if you know that it can be, in earthen kilns), and flux.

Theory does a lot of lifting that we often don’t appreciate.