Plasma first forms at thousands of Kelvin, fusion requires hundreds of million. On the journey from absolute zero to a fusion reactor, plasma is a hundredth of a thousandth of the way there.
I remember going on a physics A level class trip to JET in Oxfordshire in about '88. We were shown a graph (log) of progress so far and the target. 100,000th isn't that far out 8) I can't remember how far out they were back then but a recent improvement had chiselled away another chunk of the problem.
We were told that it would be about 50 (not 25) years to a self sustaining fusion reaction.
