How could world-wide preaching of gospel happened in 33-70AD?

This is from Sam Storms... who is looking at a parallel passage to Mark 13... Matthew 24

Preaching of gospel to whole world
8. Worldwide preaching of the gospel (v. 14)
How could this possibly have occurred in the period 33-70 a.d.' It may at first seem strange, but “fundamental principles of interpretation lead us to bear in mind contextual clues: the time indicator (‘this generation’), the audience (the disciples who ask about the temple), the specific concern (the destruction of the temple), and the harmony of the preceding signs with the first-century experience. All of these should dispose us to seek a first-century fulfillment of this verse” (Gentry, The Great Tribulation, 44). Note two important facts:
a. The words "whole world" (NASB) are a translation of the term oikoumene, which literally means an inhabited area, a standard term at that time for the Greek world, then for the Roman empire, and subsequently for the then known world. The same Greek word is used in Luke 2:1 – “Now it came about in those days that a decree went out from Caesar Augustus that a census be taken of all the inhabited earth” (oikoumene). In Acts 11:28 we read that “one of them, named Agabus, stood up and showed by the Spirit that there was going to be a great famine throughout all the world, which also happened in the days of Claudius Caesar.” Again, in Acts 24:5, “For we have found this man (Paul) a plague, a creator of dissension among all the Jews throughout the world, and a ringleader of the sect of the Nazarenes.” As Gentry notes, “a surface reading of these texts suggests global events. Yet we know these ‘world’ events happen within the Roman empire of the first century” (44). The reference to the "nations" also indicates that the point is not that every geographical area on the globe must be covered but that all the nations, i.e., Gentiles, must be reached. Did this occur? This leads to the second point.
b. Writing before the fall of Jerusalem in 70 a.d., Paul says to the Colossians:
" . . . the word of truth, the gospel, which has come to you, just as in all the world also it is constantly bearing fruit and increasing, even as it has been doing in you also since the day you heard of it and understood the grace of God in truth" (1:5b-6).
Again, Paul refers to the gospel
" . . . that you have heard, which was proclaimed in all creation under heaven, and of which I, Paul, was made a minister" (1:23).
"First, I thank my God through Jesus Christ for you all, because your faith is being proclaimed throughout the whole world" (Romans 1:8; cf. 10:18).
Thus, prior to 70 a.d. the inhabited earth had indeed heard the gospel, precisely in fulfillment of Jesus’ prophecy in Matthew 24.