Combining the idea of protobionts and the "RNA world", one can imagine the early version of "mitosis"(Mitosis is the process by which a eukaryotic cell separates the chromosomes in its cell nucleus into two identical sets, in two separate nuclei. It is followed by cytokinesis, which divides the nuclei, cytoplasm, organelles and cell membrane into two cells containing equal shares of these cellular components.)
A protobiont would accumulate "membrane" molecules while the RNA inside was replicating and catalyzing the formation of short proteins. At some point the protobiont would stretch and pull, such that it is split into two. Those RNA molecules that were less stable and did not replicate quickly would not be as numerous in the next generation as those that were more stable and replicated more quickly.
Thus, protobiont with self–replicating RNA really does represent a primitive form of life.