https://external-preview.redd.it/LkKBNe1NW51Wh-8nLSTRdQtTha2...
This chart shows how much people in the 1970s estimated should be invested to have fusion by 1990, to have it by 2000s and to "never" have it. We ended up spending below the "never" amount for research over four decades so of course fusion never happened exactly as predicted.
I think the main difference is that no one was interested in investing in fusion back then, while everyone is interested in investing in AGI now.