It's useful to go back and figure out why you believed that. Treat it as debugging your thinking. Others were saying, even back then, that nuclear and fusion had predictable economic problems.
SimCity 2000 with Fusion plants was released in 1993. To predict that solar would do this back then is asking a lot - this graph doesn't even start in 1993:
https://ourworldindata.org/grapher/installed-solar-pv-capaci...
Fusion was predicted to be an economic nonstarter at least a decade before that.
https://news.ycombinator.com/item?id=20782346
(Needless to say, I don't have a high opinion of current fusion start ups.)
And fission already had the financial fiasco of the first nuclear build out in the US.
Solar could have been predicted to get really cheap, if one had heroically projected its experience curve into the future. A lot of people chickened out doing that, even Greenpeace.
This is a ridiculous demand to make of an early teen in the pre-internet era. You know how hard it was to get information on arbitrary subjects back then like this?
That's fair, but it's also fair to ask the now middle aged person to understand their youthful errors, and to reflect on what other errors they made and might still be making.