A few are inevitable, only a question of when, not if

• The scarcity resulting from a CME breaking a lot of technology guarantees a few decades minimum of dark ages
• Something in the biosphere, whether engineered or natural, doesn't have to wipe out people but could also wipe out key crops (premise of Interstellar)
• Fertility collapse -> Gerontocracy: kind of already happening, exacerbated by economics/industrial systems. Can't be rectified by policy as it is naturally cyclical even in the animal world (exaggerated in Children of Men)

Classist/Marxist ideas of dystopia are a luxurious indulgence