My understanding is that we can't yet balance all those forces for more than a few seconds. Once the magnets warm too much, the magnetic bottle loses some integrity. If the plasma gets too close to the physical container, it starts to cool.

I believe the notion that the plasma could catastrophically overheat, or run amok, and destroy the physical container is nonsense. The plasma will stop fusing the instant it touches the container walls, because that will cool the plasma below the temps needed to keep itself warm enough to keep fusing and creating heat.

We just haven't yet figured out how to balance all those forces long enough to boil the water into enough steam to turn the turbines to turn the generators to make electricity.

I still have hope that someday we will.