Bronze, though, was also not just expensive, it was also in practice tightly controlled because it depends on tin and copper which had to come from elsewhere - in particular tin, which seems to be mainly sourced from Cornwall and Devon (or in any case definitely not available locally and would have to be transported by, probably, something guild-like). Whereas iron, as soon as means of production had reached "good enough" levels, made it possible to bypass all of that. It didn't even have to be particularly good quality. When burger joints pop up everywhere then the single family-owned restaurant suffers, or bankrupts.

Missing evidence of iron weapons among the sea people is more of a concern. But we still don't know why people became "sea people", but as I understand it a common theory is that it was due to an economic collapse which had already happened. So, the hypothesis is that the economic collapse could be (at least partly) related to the emergence of iron and its impact on the bronze cartels. Whatever the cause, the bronze age collapse as well as the origin of the sea people is very interesting.

Tin was also sourced from what is now Afghanistan.

My intuition on the "Sea People" issue is that there was both push and pull. A people change their way of life when the old way becomes less attractive (the push) and a new way becomes more attractive (the pull). The first effect could be due to environmental conditions and failure of trade, the second could be due to exposed vulnerability of the existing order of things to exploitation (the Drews theory). Positive feedback could occur on both.

At the time and in the relevant area (eastern Mediterranean), arsenical bronze was still popular which, while dangerous to create, was easy to create and didn't require tin.