It's pretty like the idea with data analytics or software ; if you can do an iteration / update by yourself in 10 minutes you will be able to solve the problem (for reasonable problems) in a few weeks for sure. If you need to spend a month assembling the data and compiling the code before you can commit a change you are simply not going to ever be able to make progress.
There are a lot of problems to deal with eg see "Fusion reactors: Not what they’re cracked up to be" https://thebulletin.org/fusion-reactors-not-what-they%E2%80%... There's also a Reddit discussion of that saying the problems aren't quite so bad https://www.reddit.com/r/fusion/comments/67rqqg/fusion_react...
If I were a politician I'd vote for subsidising the thing by say buying the electricity at 30c/kWh to advance human understanding, so I think it could be built. I think MIT estimated $5bn + to build a 200MW generator which is not a huge amount in government terms.