First, Scripture warns us that 'no man knows the times or the seasons' (Acts 1:7; Mt. 24:36ff; 1 Thess. 5:1). No man knows, or can know, the chronology of the future (This is the meaning of the Greek word chronos) nor the precise events (or timing of events) which will mark the unfolding of God's plan. Therefore, and scheme (such as that of the dispensationalists) which claims such knowledge cannot be accepted by those who believe and know the truth.
Second, Scripture clearly teaches that Christ's Kingdom is (a) already existent (Mt. 4:17; 5:3; 16:19; Mark 9:1); (b) spiritual and invisible, not worldly and material (Luke 17:20; Jn. 3:3ff; 18:36; 1 Thess. 2:12; Col 1:13); (c) everlasting, not millennial only (Dan. 2:44; 2 Pt. 1:11); (d) not the possession of Israel, from which it was taken and given to the nations (Lk. 12:32; Rev. 11:15); (e) to end, as to the present mediatorial administration, when 'he shall have delivered up the kingdom of God, even the Father; when he shall have put down all rule and authority and power. For the must reign, till he hath put all things under his feet...and when all things shall be subdued unto him, then shall the Son also himself be subject unto him that put all things under him..." (1 Cor. 15:24-28). Then will the Kingdom appear in its final form (2 Tim. 4:1; Mt. 26:29) but it will be a continuance of the same Kingdom that now is.
Third, the Bible states that Christ's return will be (a) without warning (that is, without signs) (Mt. 24:36-39, 42-44). It is compared with the days of Noah when life went on 'as usual' until, without warning signs, the flood suddenly came. Noah's preaching was the only warning, but this was not different from the preaching of today which is the only warning of Christ's coming. Christ also used as an illustration of this truth the thief that comes without warning signs, and the lightning that shines without warning from east to west. (b) He will call all men from their graves when he comes (Jn. 5:28-29; Acts 24:15). (c) In that day the heavens and the earth as we now know them will 'pass away' because 'the elements shall melt with fervent heat' (2 Pt. 3:10ff).
Fourth, the Bible says that these are the last days (Heb. 1:2; Jn 6:39; 11:24; 12:48; Acts 2:17; 2 Ti. 3:1; 2 Pt. 3:3; 1 Jn. 2:18). As John said, 'It is the last time: and as ye have heard that antichrist shall come, even now are there many antichrists: whereby we know that it is the last time.' Since one apostle asys that we live in the final days, and another says that at the end of these last days the earth as we know it will pass away, we cannot hold to another period of history in the world after these days and Christ's return.
Fifth, the great apostasy cannot be wholly future since Paul said that 'the mystery of iniquity' which causes this apostasy was already at work in his day (2 Th. 2:7ff; 1 Jn. 2:18, 22; 4:3).
Sixth, no view can be correct which envisions a period of 'good-without-evil' or the separation fo the righteous from the wicked prior to the end of this age, because Jesus said, 'In the end of this age, the Son of man shall send forth his angels, and they shall gather out of his kingdom all things that offend and them which do iniquity (Mt. 13:40-41; cf. Mt. 13:49).
Finally, no view can be correct which envisions Christ's present reign as terminating before 'he hath put all enemies under his feet.' 'For he must reign till he hath put all enemies under his feet' (1 Cor. 15:24) and 'the last enemy that shall be destroyed is death' (v. 26). It follows that entire victory must coincide with the defeat of death by the general resurrection. There can be no complete triumph of the kingdom of Christ until world history comes to an end.
I'm not pretrib.
They don't believe the world will be Christianized or "gradually get better" but that strife and conflict characterize this present age until Christ returns. Both good and evil ripen together, so there is significant cultural impact by the church in this age, yet also significant opposition even until the day of Christ's return. An inadequate summary, but good enough for a message board 
