In the last line of the poem “on shakespeare,” what does milton mean when he writes that kings would "wish to die"?

John Milton praises Shakespeare’s writing style and literary works through the poem “On Shakespeare.” He feels that Shakespeare’s invaluable works have created a place in readers’ hearts, and his fame and glory increase with the rise in the number of his readers. He also states that readers' immense love of Shakespeare's work has made those readers Shakespeare’s monument (“tomb”):

Dost make us Marble with too much conceaving

And so Sepulcher'd in such pomp dost lie,

That Kings for such a Tomb would wish to die.

Milton suggests that even kings would wish for such a monument from their subjects and would rather reside in their hearts than be forgotten. (PLATO)