To get an idea of the cost choose any cloud service and see how much you pay for the server usage by the hour. Try to llok at all the other costs involved in the business, production of dedicated content is not cheap. All the company staff, the administration and the billing have a cost.
Do not go by assumptions, measure, try to get an idea of the real costs.
Fusion is a marketing story to distract the attention. It is so difficult to realize a practical commercial fusion technology that it will not be available this century for sure.
In any case as I explained in the other comment the root cause is overpopulation. Solving the energy problems might mitigate for a while the situation, but it will not solve the situation. Famines, conflicts and mass migration will happen anyway.