Just like if you procreate, your genes are what benefit. They get passed on and kept 'alive'. For ideas the staying power of the idea and how is gets passed on is it's memetic success.

How long someone name is remembered, is a good measure. Tutanchamun for instance is one of the best known pharaohs, just because his grave was found intact. His life was quite short and insignificant, but due to his remains being found almost everyone knows his name.

Sometimes this is deliberate, rich and important people try to do much to ascertain both their genetic and memetic procreation. Sometimes it's quite accidental as the merchant Ea-nasir, who apparently delivered some sub-par copper ingots and the customer complaint survived: https://allthatsinteresting.com/first-customer-service-complaint-ea-nasir