The massive expense is, in the scheme of things, actually quite small. But there's no "there" there with fusion energy: the lower bound on its cost is the cost of fission energy.
It ain't. The lower bound on cost is the fusion energy at a safe 1AU distance. It's ignited and will produce energy for another dozen billion years. With asymptotically zero cost panels and relatively cheap batteries anyone can harness it anywhere.
Should the doge of Venice have invested any amount of money in Leonardo’s helicopter idea? There essentially was no upper bound in the usefulness of rotary wing vehicles. Yet he probably didn’t spend a single ducat. How silly.
That statement doesn't really make any sense. The expense of producing "fuel" for fusion is much lower than fission, and the improved safety profile means the actual realized engineering costs will also be lower.
Yes, in theory, if you could convince the world to accept thousands of new fission plants, you could probably get the cost pretty low, and that low cost would be pretty close to the same outcome for fission. But, good luck with that! Fusion has a much better chance of actually achieving the theoretical long-term economics of fission.
The cost of Ph. D.s to operate the fusion reactor, vs the cost of associate degrees to operate a fission reactor. Also, the short life and disposable nature of the fusion reactor vessel - most proposals deal with neutrons by ablating lithium from the inside wall of the reactor vessel. And disposal costs, much more radioactive material to be disposed of than with fission, and it can't be reprocessed into fuel either. Also, the ancillary equipment needed for startup, and for operation, is much more expensive.
The list goes on. The more you look, the worse it gets.
