Never claimed "heaven is on earth".
I claimed that the resurrection of the dead involves earth. I don't pretend that "all Christians" think this way, but it is the orthodox teaching of the Christian Church, it's what Scripture says and what the Church has confessed for two millennia.
The idea of spending eternity in a place called Heaven is, objectively, not the orthodox teaching. It's not what Scripture says and it's not what Christianity has said for the last two millennia.
Individual Christians very often do disagree with the historic teaching of the faith, or simply are ignorant of it; but that's not relevant.
The Creeds are clear, we believe in the resurrection of the body and the life everlasting in the age to come. Scripture is clear about the renewal and restoration of creation, "I saw a new heavens and a new earth" "Behold I make all things new".
The idea of an eternal bodiless existence "out and up there" fits a lot better into Gnostic or Manichean ideas, but has no merit within orthodox Christian eschatology which affirms the resurrection of the body and the redemption of all creation.
-CryptoLutheran