nothing in hardware is cheap until it scales up. in fact, the cost vs. scale dynamics are well understood, see Wright's Law.
the "huge assumption" is our entire roadmap... and the major things that drive cost-down are: (1) increased carbon yield by integrating existing pyrolysis technology, (2) shrinking transport distances by operating pyrolysis near injection wells, and (3) increased throughput by making our pyrolyzers larger. these take time, but are hardly shooting for the moon.
Still, I will allow myself to provide some feedback. There's a chance that in your position as the CEO of a startup (and an MIT graduate), maybe not a lot of people are willing to tell you thinks that they think you won't like to hear.
It looks like your business model involves carbon sequestration (you just mentioned here "injection wells", plus it's in the last figure of the article). That means you are proposing a process that smelts iron ore using hydrogen rather than coke. Something like this plant in Sweden [1]. There are two problems now. One is that you are making the assumption that it's quite easy to get such plants in the US too, but the recent history is not very promising ([2], [3]). The second problem is that you are a step ahead of what people want right now. Most people would be happy to make net-zero steel. You are pitching something that is net-negative steel. A lot of people will say it's laudable, but they are not willing to pay extra for that. And if net-zero is their goal, then you need to compete with steam reformation using natural gas. And I don't think this is possible in any scenario, not matter how heroic assumptions about economies of scales or learning curves, or technological improvements one makes.
the "huge assumption" is our entire roadmap... and the major things that drive cost-down are: (1) increased carbon yield by integrating existing pyrolysis technology, (2) shrinking transport distances by operating pyrolysis near injection wells, and (3) increased throughput by making our pyrolyzers larger. these take time, but are hardly shooting for the moon.