There is no indication whatsoever anywhere in Revelation that chapters 4 and following pertain to the future in their entirety. Clearly some portions do, but others explicitly refer to both the past and present relative to the first-century audience (e.g. Rev. 17:10). Perhaps the most obvious example of this is the birth of Christ as prophesied in Revelation 12:1-5.

In Revelation 12:6, by the way, the 3 1/2 years are the period in which the "woman" who gives birth to Christ is to be nourished and protected in the wilderness. Because the Satan is so enraged by this protection of the "woman," he goes off to persecute her children -- namely Christians (Rev. 12:17) -- during this period.

This is all to take place when Satan is thrown out of heaven (Rev. 12:9) and when the kingdom and authority of Christ have come (Rev. 12:11). All of these things have already taken place. Satan fell from heaven during Jesus' earthly ministry (Luke 10:18) because Jesus was exercising his authority (e.g. Matt. 7:29; 8:9-13; 9:6-8; 10:1; Mark 1:22,27; 2:10; 3:15; 6:7; Luke 5:24; 7:6-10; 9:1-2; 10:19; John 5:27; 10:18; 17:2) as he inaugurated his kingdom. Here's my favorite verse proving that Jesus already has all the authority that will ever be given to him: "Then Jesus came to them and said, 'All authority in heaven and on earth has been given to me' " (Matt. 28:18). The kingdom of God is here and now (e.g. Matt. 12:28; Luke 11:20; 16:16; 17:20-21) because Jesus the King has received his kingly authority and been seated on the throne (Eph. 1:20-23; 2:6; Col. 3:1; Heb. 8:1; 12:2; Rev. 1:4; 3:21). True, it is not yet here in all its fullness, but it is here nonetheless. Thus, we find the Bible speaking of the kingdom as both already here and not yet here (a good book on this is The Coming of the Kingdom by Herman Ridderbos [P&R Publishing]). But the fact that it has not been realized in its fullness does not refute the fact that it has already begun.