He wants to emphasize that each person can become a famous person, and that each person from the village could've become famous. He also emphasizes that eventually both the common people and the leaders and poets end up the same, and that death is inevitable.
In
“Elegy Written in a Country Churchyard,” Gray compares the dead
of the little village to famous leaders and poets in order to
emphasize the importance of the people and the idea of human
mortality. It conveys the feeling that in death there is no
difference between common and extraordinary people.
