A lot of human, throught humanity's history, had the material means to live a pretty pleasant, labor-free life, and yet chose a different path, away from hedonism. I suppose this will still be true many centuries from now.
Pretty much any organism that manages to develop the intelligence to build a starship will have a long history of evolution. Their mindset will presumably be guided by ancient evolutionary pressures. For us humans, we're partially motivated by a desire to explore and understand our surroundings. I think it's realistic to assume that at least some subset of aliens should be motivated by the same exploration drive.
