I think that is a fair point and an interesting observation. Are there two thrones; one in heaven and one on earth? I would tend to say no and I would point to this verse (among others).
and again...
Mat 23:22 And he who shall swear by Heaven swears by the throne of God, and by Him who sits on it.
This touches on something that I, quite frankly, have never figured out-the physical and the spiritual. Satan is a physical being roaming around like a lion, but we don't see him. Likewise we know angels are everywhere. Indeed, we are told in scripture that we might treat them "unaware". Yet we would call them spiritual beings. There is no indication that the garden of Eden was ever destroyed, and every indication that it still exist guarded by angels, but where is it? We even know the general whereabouts but can any of us find it?
I bring this up because I don't think one can clearly distinguish from the "spiritual" and "physical". They appear to be intertwine like different spectrum of light. A slight shift in the wave pattern and one has a completely different perspective.
Just because we cannot see a physical throne going from heaven to earth does not mean that a physical throne doesn't exist. Christ was physical but upon His resurrection would appear and disappear. (I might add He did this before His death as well.) How we will be in our glorified bodies is difficult to understand. Somehow we view ourselves as we are now, walking around on some celestrial cloud. I'm not sure if that's the right perspective.
A physical throne reaching from heaven to earth right now doesn't seem to be all that preposterous when we can't even find Eden located on the Tigris and Euphrates.
Thank you for the scripture --- it one more time refutes the preterist position. Read it carefully. It says that heaven is God's [the Father's] throne and Jerusalem is the city of the great King.
Bingo ----
"At that time they shall call Jerusalem the throne of the Lord, and all nations shall be gathered unto it, to the name of the Lord, to Jerusalem, neither shall they walk any more after the imagination of their evil heart."[Jeremiah 3:18]