> Since the fusion fire only ignites at temperatures of over 100 million degrees, the fuel [...]
Would it be accurate to say that this gets us 20% of the way there, or is that overly simplistic?
Note that Wendelstein 7x will never operate to produce actual fission with DT fuel, because that is (a) outside its mission goal, which is to research plasma behaviour at conditions close to what is needed in a power plant and (b) dealing with the neutron bombarding creates all sorts of complexities in terms of the blanket. Not really solved here as well, as Wendelstein 7x is a nightmare to disassemble and upgrade. For a power plant maintenance and serviceability needs to be build into the design. And (c) they don't have the government permission to deal with nuclear material and nuclear waste.
So no, we are not 20% there. But we have proven that (a) the Stellarator actually has wings, and (b) plasma physics so far behaves mostly as predicted. Especially the latter is something to be celebrated, because plasma is nasty in terms of physical properties, really complex to model, etc.