> it wouldn't solve the problem of needing a supply of carbon atoms to make the carbon-based substances in the list.

How many of that could be substituted with biomass? We're already making natural gas replacements using feces, food and agricultural waste, and we're making diesel fuel replacements - in case of doubt, at least older diesel engines can burn straight olive, sunflower or rapeseed oil, just modern ones will possibly incur expensive damage in the high-pressure fuel distribution section.

> You can't make insulin, brake fluid or PVC out of electricity alone.

Insulin is made with GMO bacteria these days, so all we need is something to feed the bacteria with, IIRC it's glucose which you can easily create from any sort of starch-containing plant.