Predicting anything related to science discoveries past a 15 year threshold is almost impossible. There are so many frontiers on which science advances that predicting which one will hit the crucial break-thru that will alter human life as we know it is an art.

Consider - Nano tech might make such a breakthru to make machines unimaginable today common place, Or medicine may make living to 150 trivial or Genetic manipulation may make extreme modifications easy, Or chemistry might make exotic metamaterials possible, Hardware/Software may make a True Human scale AI feasible or some kind of Man-machine hybrid trvial. Any ONE of these could alter the shape of Humanity in the next 20 years.