https://en.wikipedia.org/wiki/All_Men_Are_Mortal a great book on this. It shows how the immortal are withered away by time and futility of there attempts to change history and be a permanent influence.

Meanwhile, the mortal while shortlifed and with only one poker chip in the game, play and win/loose with all the passion they have and form a sort of river, that withers the immortals plans and dreams down to zero.