>I would expect a huge mass of simple RNA based life forms simpler than prokaryotes. There is such a mass: viruses. As such, we know that cellular life has evo

>I would expect a huge mass of simple RNA based life forms simpler than prokaryotes. There is such a mass: viruses. As such, we know that cellular life has evolved multiple mechanisms to efficiently kill external RNA. If cellular life can efficiently outcompete non-cellular life for resources (and perhaps for RNA itself), then this outcome is not unreasonable at all. Counter-example: There are (far) more Homo sapiens on the planet than other primates in total.