What that that paragraph means is that things that do not exist will cost money to bring into existence. A significant amount. It's not a critique. This is not new. This is not a fusion problem. There is an initial cost and development to any new technology. This technology is particularly difficult, however. It's also sustainable real renewable energy. You have to worry about actually being able to invent something before you can worry about saving money on that thing. Look up how much the Manhattan Project cost! This shit is not software engineering; It's really really fucking complicated it will cost a load of money.

We don't really know what path fusion research will lead to. It's science. We don't know what we could find out tomorrow that could apply this research. But even the promises of commercial power generation alone should be enough to keep funding the project whether it will happen in 50 years or 100 years. It's not like they aren't making progress. You can't rush research and also under fund them.