Why those seven churches in Revelation, and not others?

Were they chosen because they were representative?

Was it because seven often is used to show completion, and also perfection?

How meaningful is it that John wasn't told to write to one universal church?

Were they churches that the apostle John already had a close relationship with?

When we read it, can we consider it multiple ways simultaneously?

1. That each church was an actual church in John's day, with special and unique qualities, that we can learn from?

2. That we can see both the encouragements and the rebukes, of each of them, applied to ourselves, as well as our own church?

3. That there may be kinds of churches today, that are not unlike those seven churches, or even combinations thereof?

4. That they may show and represent the condition of churches in the very last days before the blessed hope?

5. That they may represent church history from Pentecost to the blessed hope?

If that fifth case might also be true, then with the order they are given in, is it only coincidental that that on a map,

that order goes in a clockwise direction, the direction that time goes in?

I have read that the ancient Assyrian archives refer to Magog being the location where those seven churches would be centuries later.

That those records indicate that what they called Magog was not part of the Assyrian empire, but actually helped Assyria, against some common enemies.

And also what about that Pergamos is where Jesus said Satan's seat is, not his altar, and that at the end, Satan give's that seat to the beast?

Revelation 2:13 I know thy works, and where thou dwellest, even where Satan’s seat is: and thou holdest fast my name, and hast not denied my faith, even in those days wherein Antipas was my faithful martyr, who was slain among you, where Satan dwelleth.

Revelation 13:2 And the beast which I saw was like unto a leopard, and his feet were as the feet of a bear, and his mouth as the mouth of a lion: and the dragon gave him his power, and his seat, and great authority.

Revelation 16:10 And the fifth angel poured out his vial upon the seat of the beast; and his kingdom was full of darkness; and they gnawed their tongues for pain,

Could the seat of the beast, therefore, be in that same location, which is in western, modern day Turkey?