I think the key point in here is the tech side. Iron Ore is a...

I think the key point in here is the tech side. Iron Ore is a game of politics and bulk material handling. From an engineering perspective it's not that complex and it's highly repetitive. You can use simple steels, coatings and ceramics and the consequences of equipment failure are relatively low.

Compare that in the first instance making green hydrogen & storing it which is well understood but there is likely much room for improvement. You also start talking more bespoke equipment, higher grade steel's and coatings, and more chemical processes. Take that to the next step where you're shipping it either as ammonia or LNG (Methane) and you escalate that difficulty, and therefore cost, again. A single LNG train could very comfortably cost more than Iron Bridge in its entirety and is a temperamental but of kit.

AF has succeeded in doing something with FMG that few people thought possible, breaking the IO duopoly of BHP and Rio but how much of that transfers to a chemical processing business remains to be seen.

Anaconda Nickle showed what happens when you get things wrong with chemical processing (or when you try to cut the cost to be cheaper) and Ammonia/Hydrogen/Methane are all high energy explosive materials so you want to get it right. It's why I have every hope AF/FFI/FMG succeed but I have more faith in the O&G Majors pulling it off.