Everyone is going to die, but few will be remembered. Those who first go to Mars will be remembered long after their deaths. Whether they are remembered as being crazy or colonizers, they will be remembered. For many that is enough.
There's even a saying : "nobody remembers the second person who climbed the Everest".
We're talking about colonization, not Everest-like conquest. Most colonizers will be anonymous. Whatever goals they'll have, fame will not be one of them.