I find it hard to imagine a future where fusion power would be cheap. The reactors will most likely be highly complex, with very expensive materials and lots of custom parts. Fission reactors are much simpler and even they have become too expensive to run without subsidies. ITER is supposed to cost 22 billion, but the US DOE estimates it will be closer to 65 billion. And ITER is a tiny test reactor that will still draw energy from the grid while running. If we ever get a fusion reactor that can actually produce energy, it’s going to be so much bigger and more complex than ITER. And it will have a maximum output and operating life, so a finite amount of energy it can produce during its lifetime. Divide the cost for R&D and construction by the amount of energy produced, and it will most likely come out as much more than solar/wind + storarge.