If you grant moss and bacteria, then more complex life forms become inevitable. There are _advantages_ to be being multicellular, or multicellular life wouldn't

If you grant moss and bacteria, then more complex life forms become inevitable. There are _advantages_ to be being multicellular, or multicellular life wouldn't exist. It's energetically advantageous for a plant to acquire a woody stem and stand up above the moss, or for a simple organism to work out how to have eyes, or teeth, or legs, or an exo- or endoskeleton. Assuming an environment that affords nutrients and is stable over a long time, once life kicks off it should keep complicating itself. It wouldn't stop at simple forms.