It makes absolutely no sense to wish to remembered after one dies unless one believes in the communication of the diseased with the living.
What about to leave a legacy that will inspire future generations to follow in your footsteps, to influence others to continue to work towards the same goals as you did during your life? What you said makes sense on a selfish level, but what about those who also care for humanity or the planet as a whole? Some peoples lives are interesting and inspiring to others, if not there would be no need for biographies .
You won't be able to receive the pleasure because you will be dead. So we rather say a story to our heads now. We live with a false promise. Even if it happens we won't get anything out of it other then the false hope we feed ourselves in the present.
But if someone knows that he is doing something great for future generations (including his children if he has them) that won't be understood or appreciated by other people at the present moment, if he is an altruist he can still enjoy (receive the pleasure) from just knowing that he is doing a great thing. Cheers!