if something better were possible, it probably would have evolved by now
I don’t think this argument works. Adaptive evolution has mostly been driven by DNA mutations and natural selection. DNA is transcribed to RNA and then translated into proteins. I’m not sure evolution (of Earth’s cell-based life) could produce something radically different, because this central mechanism is so fundamental and so entrenched.
You could be right; the cellular machinery hasn’t changed very much for ages, so it certainly could have gotten caught in a local optimum. We don’t know very much about what life looked like before modern cells, so we don’t know what our current cellular machinery competed against.
I don’t think this argument works. Adaptive evolution has mostly been driven by DNA mutations and natural selection. DNA is transcribed to RNA and then translated into proteins. I’m not sure evolution (of Earth’s cell-based life) could produce something radically different, because this central mechanism is so fundamental and so entrenched.
You could be right; the cellular machinery hasn’t changed very much for ages, so it certainly could have gotten caught in a local optimum. We don’t know very much about what life looked like before modern cells, so we don’t know what our current cellular machinery competed against.