[ianai]

Because that question is more of an economics research paper or policy brief than a mass media article. And in that arena data are currency, ie largely not public.

Generally, there’s a lot of economics principles at play. Economies of scale mean as more is produced, often, still further increases in production are possible more cheaply than previously obtained. First semi chip produced might cost billions. The billionth chip might be pennies. There’s also a concept in the environmental economics that pulling finite resources out of the ground responds to increasing demand similar to pulling more money out of a bank via loans. Ie the most easy to obtain resources are mined first and the cost increases from there. In practice, too, producer relationships matter. A company buying batteries for EVs (ie at that scale) for their 5th year in a row is going to have demonstrated to their suppliers that, indeed, they can write a check for all the materials they’ve ordered much more than in year 0. So their suppliers have better information about how reliable their needs are, and so on.

Lots of complicated things not generally in the public knowledge nor easy to explain quick enough to not get scooped by another organization.