Has the gospel been preached to the world?

Has the Gospel Been Preached to the Whole World Already? (John Piper)

"From Rob Bell to Peter O’Brien, Colossians 1:23 proves a challenge. Paul refers to the gospel of his day as “the gospel . . . which has been proclaimed in all creation under heaven” (ESV). Commentators multiply explanations of how the gospel could have already been proclaimed “in all creation” in the first century. The context:

You he has now reconciled . . . if indeed you continue in the faith, stable and steadfast, not shifting from the hope of the gospel that you heard, which has been proclaimed (Greek tou kēruchthentos) in all creation under heaven.” (Colossians 1:21–23, emphasis added)
Here is my simple solution, though you have to know Greek to see it. The Greek for the phrase “which has been proclaimed” is tou kēruchthentos). This is a substantival participle which we could render “the proclaimed one” in English. It is in apposition with “the gospel” (tou euangeliou . . . tou kēruchthentos)—“the gospel . . . the proclaimed one.” The fact that the participle “proclaimed” is aorist tense does not mean the proclamation has already happened in the past. That is not the way aorists in substantival participles work, as Daniel Wallace makes clear in Greek Grammar Beyond the Basics (note 8, 615)...."