It's not about overpopulation.

People used to live in caves in a static way of life that persisted for generations. Hunter gatherer societies still exist. While I can't speak for them I'm very happy that I live in modern society as compared to theirs.

> There's just not any benefit to exploring space.

I strongly disagree, what are the benefits of living? Benefits are relative and arbitrary, there are no universal definition of 'benefits'. Access to more resources and potential to leave solar system would count as benefit to me. The simple experience of just not being stuck on Earth would be another one for me.