How can we know the costs will be this low? Fusion reactors today have thus far been very expensive to build.

Driving down costs will require continuous operation and low maintenance. To my knowledge there is no clear answer to how this will be achieved in the near future.

Maybe they can achieve positive power output in 10 years. But do you really think that once this is achieved they can run it for 24/7?

Does it not seem more likely that they may pull off a few minutes at a time and that longer periods will require years of improvements?

I am just judging on what we have seen thus far. It seems like it is very challenging to increase the length of the operations. I cannot see how we are suddenly supposed to go from a few seconds to whole days.

Maybe you can give me some links to these reactors . Perhaps I am being too negative. I am interested in getting a better overview of the current state of fusion.