Final answer:
The text suggests that a reader might mistakenly believe nuclear fusion will be a viable power source soon, despite significant challenges making this unlikely in the near future.
Step-by-step explanation:
Based on the language used in the excerpt, the mistaken belief a reader might form is that nuclear fusion will be a power source in the near future. The texts reference ongoing research and speculate on fusion energy's potential, but clear hurdles such as high costs, technical complexity, and unsolved problems like radioactivity management are highlighted. The excerpts mention facilities like ITER, which is an experiment not expected to produce electricity and has an operational date aimed at 2035, indicating that fusion as a reliable power source is not imminent.