The "end of the system of things" in the context of the Jews Jesus was speaking of was the "end" of the "appointed times of the nations." It was not the end of the world as we know it in generation.
The Jews were being punished and were under gentile rule. Then they were punished by going into exile. They would remain in exile until the "appointed times of the nations" ended. When that occurred, they would be restored to their homeland again and thus the "end of the system of things" of the gentile times would occur. They were not concerned about Armageddon, but when they would have control over their homeland again.
Therefore, the "end" that is mentioned in Matthew occurred on November 30, 1947.
The specific reference that the "good news" would be preached around the world just before the end came is a very specific fulfillment. That is, earlier that year in 1947, Brother Knorr literally went on a worldwide preaching tour. This proved the good news had reached around the globe but it also literally fulfilled this prophecy. That is, when the "good news" was preached around the globe during this speaking tour, then is when the "end" of the gentile times would occur, which it did on November 30, 1947.
So this prophecy was fulfilled! Truly, if one does not have the correct understanding or interpretation then it might seem prophecies in the Bible have not come true.
"Proclaimers" Page 98: "With a view to worldwide expansion, on February 6, 1947, the Society’s president and his secretary, Milton G. Henschel, embarked on a 47,795-mile [76,916 km] world service tour. The trip took them to islands of the Pacific, New Zealand, Australia, Southeast Asia, India, the Middle East, the Mediterranean area, Central and Western Europe, Scandinavia, England, and Newfoundland. It was the first time since 1933 that representatives of the Society’s headquarters staff in Brooklyn had been able to visit their brothers in Germany. Jehovah’s Witnesses around the world followed the two travelers as reports of the trip were published in issues of The Watchtower throughout 1947."
So this prophecy was fulfilled. NH Knorr literally preached the "good news" worldwide early in 1947, and then the "end" came on November 30, 1947.
WAKE-UP CALL: Now, think about this folks. Think of the context of the "great tribulation" that most witnesses think is Armageddon noted in Matthew 24. People are told to flee to the mountains. How can that save you from Armageddon? Women with small children will sufer a fate worst than those who are able to run? Is that really Armageddon? Plus, the days were cut short for the sake of the "holy ones" for if not, "no flesh would be saved." That is, this tribulation would wipe out even more of the "holy ones." Does Armageddon exterminate holy ones along with the wicked at Armageddon? NO. This "great tribulation" which is clearly over before the messiah arrives is a reference to the HOLOCAUST and the "holy ones" who are killed in the majority is a reference to the Jews. When the prophecy mentions "flesh" it is talking about the literal Jews.
So fulfillment of prophecy is 100% dependent on the right understanding. You now have the right understanding, and thus you can see this was beautifully fulfilled!! The "end" is not Armageddon, but the end of the gentile times, which ended on November 30, 1947. Before that, NH Knorr preached the "good news" around the globe, fulfilling this prophecy.
Jehovah grants understanding to those he chooses. Clearly the WTS is out of that loop! But all of us don't have to be. The true understanding of these prophecies is available now for those who want that truth.