Somewhere there was an excellent blog post that I lost the link to that explains that fusion and nuclear have basically the same requirements for energy extraction. You can therefore estimate the ideal cost of a perfect fusion reactor and zero out the cost of the generation side and get a rough estimate of the lowest possible cost for fusion with current technology. I think that put you at somewhere near the 20c mark. Solar is 4-5c and going down, it’s hard to beat that.
Also you have to be careful when comparing solar to fusion because there are significant lifecycle costs on fusion that are not present in solar. So you have to take that into account when calculating total cost
This is why I think the only fusion approach that possibly has a chance is Helion's, since it avoids the turbines of the heat -> electricity approach that fission and DT fusion use.
