Externalities 50 or 100 years down the road tend to have little influence on economics. Parent strongly predicted commercial fusion in 30 years. That will not happen.

A vacuum chamber containing 150,000,000 K plasma surrounded by molten lithium blankets surrounded by liquid-helium cooled superconductors. Yeah, that sounds cheap.

Solar, anyone? Somehow I don't see $73/watt 7 years from now competing with $19/watt right now (of which about $5 is the panels) and falling fast. I'm assuming 13% capacity factor for solar here, which is pessimistic (Northeast US).

I am aware of iter. The proposed claim to be defended is "commercial fusion power by 2040", not "there exists an international experimental project to figure out how to create a fusion reactor with a positive energy balance and an economic durability, neither of which we know how to do yet."