Yes, and I'm not sure that's a fair description. As far as I can tell, MIT's reactor has been producing as much useful data as the other ones; and I don't think the other US projects, or ITER, have a significantly better chance than MIT's of achieving ignition, which is supposed to be the goal that makes all this worth the taxpayer's money. See my response to nitrogen 51 upthread.

I think people here are overestimating how well we understand plasma science. I don't have a PhD in that field, but my friends who do seem to think there is still an awful lot of basic science that is just... not there yet.

This may be true if by "basic science" you mean being able to rigorously derive the behavior of a complex system like a plasma from first principles. I don't have a PhD, but I have a Master's in Nuclear Engineering, and a lot of the plasma physics I studied while getting it was full of heuristics and phenomenological laws rather than rigorous or at least semi-rigorous derivations from first principles.

However, it's not clear that we need to know all that to achieve controlled fusion, and the fusion reactors that are being pushed for global funding are not being pushed as improving our basic science about plasma physics. They are being pushed as engineering efforts that will achieve ignition. As I said in another post upthread, we know what conditions we need to achieve for ignition; we just don't know how to engineer a device to achieve them. That's what ITER and these other devices are supposed to help us figure out.

Thanks for the clarification. What I meant by "basic science" was that we were able to model plasmas well enough to predict what would happen with something akin to CFD given a real model of the apparatus. So if you can do that with heuristics and "laws", that would meet my definition of "understood".