I believe if life is common than there must of been at least one group of aliens that at least attempted to colonize it self everywhere in space?
Unless humans are a extreme anomaly and that most other aliens don’t really care about space exploration, and just focus on their home planet.
Eh, the evolutionary mechanism is simple though, even if the process is complex. Those mechanisms that aren't as reliable are out competed by those that are, leaving us with mostly reliable ribosome activity (environment non-withstanding). What would be interesting to see is what those more unreliable methods looked like.
Not that this rules out deism, it's just that self-replicating biological life has it's own rules here.