Every depression in human history has been a fuel scarcity problem in disguise. Fusion eliminates scarcity at the source. The fuel is seawater. The waste is helium. A reactor is hitting the real grid by the early 2030s using superconducting magnets and plasma confinement tech that didn't exist just five years ago. The science is solved. The engineering is being built. If the current timeline holds, the 20th century's entire energy infrastructure becomes a historical footnote within a single generation.