The argument the author seems to be trying to make is that fusion power will never be realistic because it'll be too expensive. Then goes on to explain why it'

The argument the author seems to be trying to make is that fusion power will never be realistic because it'll be too expensive. Then goes on to explain why it's expensive today. You could make the same exact argument about wind and solar a few decades ago. Also, there's a TON of assumptions in the arguments he's making. For example, he takes an existing fusion reactor design and assumes every one built from now until forever will be exactly the same or that they'll even use the heat->steam method of energy extraction. When it comes to fusion you can extract energy energy from the charged particles themselves via Aneutronic Fusion (https://en.wikipedia.org/wiki/Aneutronic_fusion https://en.wikipedia.org/wiki/Aneutronic_fusion) and skip that 1-meter-thick lithium shielding and a whole lot of other expensive things.