This idea is called the "Great Filter." https://en.wikipedia.org/wiki/Great_Filter https://en.wikipedia.org/wiki/Great_Filter Another option is something like

This idea is called the "Great Filter." https://en.wikipedia.org/wiki/Great_Filter https://en.wikipedia.org/wiki/Great_Filter Another option is something like the outcome of the novel Blood Music, where engineering efforts become smaller and smaller and the outside universe is ignored completely in favor of microscopic exploration and engineering efforts. https://en.wikipedia.org/wiki/Blood_Music_(novel) https://en.wikipedia.org/wiki/Blood_Music_(novel)