Nice try, Michelangelo. Millions of tourists take photos of your David every year, but it's going down, just like the toppled statues in line 5. Although the speaker doesn't name any names, Sonnet 55 reads like an in-your-face bumper sticker to other artists: Poetry 4 Ever. And here's the logic: because other kinds of art, like statues and architecture, are material (made of physical things), they are fundamentally transient: war or time or even a big storm can destroy them. But because poetry is immaterial, made of nothing but words, it is also eternal. Nothing can destroy it and it can preserve the memory of a person as long as readers continue to read it.
Sonnet 55 offers a declaration of war from poetry against all other art forms. En garde, sculpture.
In Sonnet 55, the speaker argues that poetry is the only creation that can outwit time and death. Powerful stuff that poetry.