Earth will die eventually. It might be in ~5 billion years when the Sun itself dies, but the planet will not last forever. To have any hope of lasting on a cosmic time-scale as a species, you need to spread across the stars.
There is a very slim chance that somewhere in that vast time-scale horseshoe crabs might evolve intelligence and the ability to manipulate their environment such that they eventually build some kind of means of interstellar travel, but given we're using up resources like coal that will never be replenished, mining all the easy accessible metals, etc. I don't believe it will be possible for another civilisation to rise equivalent to humans in technology, let alone a star faring civilisation.
Being smart is what made us the dominant species on this planet, and being smart is the only thing that will get us out of the solar system - really, it's all we have going for us. The crabs might have better immune systems and so on, but I believe that eventually (if we don't destroy ourselves) we'll reach a point where our ability to edit the human body would allow us to patch in a better immune system.
There is a very slim chance that somewhere in that vast time-scale horseshoe crabs might evolve intelligence and the ability to manipulate their environment such that they eventually build some kind of means of interstellar travel, but given we're using up resources like coal that will never be replenished, mining all the easy accessible metals, etc. I don't believe it will be possible for another civilisation to rise equivalent to humans in technology, let alone a star faring civilisation.
Being smart is what made us the dominant species on this planet, and being smart is the only thing that will get us out of the solar system - really, it's all we have going for us. The crabs might have better immune systems and so on, but I believe that eventually (if we don't destroy ourselves) we'll reach a point where our ability to edit the human body would allow us to patch in a better immune system.