We are not in the "end times" because we are well past them.
The "end times" - as Christ and the apostles saw them - began and were signified by the events surrounding Christ's advent, earthly ministry, crucifixion, resurrection, and ascension to the right hand of the Father, and ended with the destruction of Jerusalem and its temple, thus bringing to an end forever the last vestiges of the Old Covenant (Law of Moses.)
And here is how those "end times" played out in the gospels and Revelation...
{3} As He was sitting on the Mount of Olives opposite the temple, Peter and James and John and Andrew were questioning Him privately, Mark 13:3 (NASB)
By this verse, we see that John is one of the four disciples sitting on the Mount of Olives for the Olivet Discourse, yet it appears nowhere in his gospel.
While the other gospels dedicate 1 or 2 full chapters to the Olivet Discourse, John wrote a whole book about it (Revelation), and here's just one of the clues for understanding that:
Look at Matthew 24:9
{9} "Then they will deliver you to tribulation, and will kill you, and you will be hated by all nations because of My name. Matthew 24:9 (NASB)
This is the same tribulation He tells them they will face in Matthew 10:
{16} "Behold, I send you out as sheep in the midst of wolves; so be shrewd as serpents and innocent as doves. {17} "But beware of men, for they will hand you over to the courts and scourge you in their synagogues; {18} and you will even be brought before governors and kings for My sake, as a testimony to them and to the Gentiles. {19} "But when they hand you over, do not worry about how or what you are to say; for it will be given you in that hour what you are to say. {20} "For it is not you who speak, but it is the Spirit of your Father who speaks in you. {21} "Brother will betray brother to death, and a father his child; and children will rise up against parents and cause them to be put to death. {22} "You will be hated by all because of My name, but it is the one who has endured to the end who will be saved. {23} "But whenever they persecute you in one city, flee to the next; for truly I say to you, you will not finish going through the cities of Israel until the Son of Man comes. Matthew 10:16-23 (NASB)
Now, look what He tells the chief priests and scribes in Matthew 23:
{34} "Therefore, behold, I am sending you prophets and wise men and scribes; some of them you will kill and crucify, and some of them you will scourge in your synagogues, and persecute from city to city, {35} so that upon you may fall the guilt of all the righteous blood shed on earth, from the blood of righteous Abel to the blood of Zechariah, the son of Berechiah, whom you murdered between the temple and the altar. {36} "Truly I say to you, all these things will come upon this generation. Matthew 23:34-36 (NASB)
He told the disciples they would be persecuted (face tribulation). He told the Sanhedrin they would persecute His messengers and would be held accountable for it.
Again, this is the persecution (tribulation) mentioned in Matthew 24:9.
But there is another tribulation mentioned in Matthew 24!
{21} "For then there will be a great tribulation, such as has not occurred since the beginning of the world until now, nor ever will. Matthew 24:21 (NASB)
The tribulation of Matthew 24:9 is, therefore, both a cause and a sign of the "great tribulation" that would befall Jerusalem! (The language used in Matthew 24:21 is the same prophetic language used in the OT to describe the judgment of Jerusalem at the hands of the Babylonians.)
So now, with all this in mind, the next time you read the book of Revelation, think about this: the word tribulation (Greek: "thlipsis") is used only 5 times in the book of Revelation, and it's always used in association with believers (the tribulation of believers mentioned in Matthew 10 and 24).
After Revelation 7:14, however, that word is never used again in the book of Revelation! From chapter 8 until chapter 20, the focus shifts from the tribulation of believers to the outpouring of God's wrath. This is consistent with the "great tribulation" of Matthew 24:15-28 and Luke 21:20-24.
In other words, what Matthew, Mark, and Luke discuss in a few verses, John discusses in 12 chapters: the (final) judgment of Jerusalem and Judea.
The evidence for this can be seen in great detail, especially in Revelation 17-19, but can be summarized in just a couple of verses (thanks for bearing with me):
{9} When the Lamb broke the fifth seal, I saw underneath the altar the souls of those who had been slain because of the word of God, and because of the testimony which they had maintained; {10} and they cried out with a loud voice, saying, "How long, O Lord, holy and true, will You refrain from judging and avenging our blood on those who dwell on the earth?" Revelation 6:9-10 (NASB)
(This is the same vengeance Christ has promised would befall the chief priests and scribes in Matthew 23.)
{6} And I saw the woman drunk with the blood of the saints, and with the blood of the witnesses of Jesus. When I saw her, I wondered greatly. Revelation 17:6 (NASB)
(The harlot is 1st century Jerusalem, which crucified Christ and slew His messengers beginning with Stephen. If you look at how she is dressed, you will see she is wearing the same vestments of the Levitical priesthood seen in Exodus.)
{24} "And in her was found the blood of prophets and of saints and of all who have been slain on the earth." Revelation 18:24 (NASB)
(Seeing the connection yet?)
And finally:
{1} After these things I heard something like a loud voice of a great multitude in heaven, saying, "Hallelujah! Salvation and glory and power belong to our God; {2} BECAUSE HIS JUDGMENTS ARE TRUE AND RIGHTEOUS; for He has judged the great harlot who was corrupting the earth with her immorality, and HE HAS AVENGED THE BLOOD OF HIS BOND-SERVANTS ON HER." Revelation 19:1-2 (NASB)
There is only one city in history that slew both the OT prophets and NT witnesses of Christ: Jerusalem. This is how the gospels are inextricably linked to Revelation: through the Olivet Discourse.
Sorry for the long post.