It can only be experienced in the spiritual sense ever, unless there ends up being a kingdom that has laws written in law books in a physical kingdom somewhere with an administration and political apparatus.
Maybe we are just not understanding in the spiritual sense and in the literal physical sense, the same way?
Take angels for instance. Though people have seen angels before, typically one does not see them with the naked eye. This would be an example of experiencing the kingdom in a spiritual sense. Plus it requires faith to believe in beings one has never even seen.
When Jesus returns though, these angels one currently can't see, but have faith they exist, these things will no longer be an issue. One will be able to see them as plain as the nose on their face. This being an example of the kingdom in a literal physical form.
Earlier I brought up the parable in Luke 19. Amils typically believe the entire planet literally goes up in flames, burning up everyone on the planet in the process, yet when comparing to the parable in Luke 19, as an example, no such thing is being depicted at the time.
Luke 19:15 And it came to pass, that when he was returned, having received the kingdom, then he commanded these servants to be called unto him, to whom he had given the money, that he might know how much every man had gained by trading.
16 Then came the first, saying, Lord, thy pound hath gained ten pounds.
17 And he said unto him, Well, thou good servant: because thou hast been faithful in a very little, have thou authority over ten cities.
18 And the second came, saying, Lord, thy pound hath gained five pounds.
19 And he said likewise to him, Be thou also over five cities.
20 And another came, saying, Lord, behold, here is thy pound, which I have kept laid up in a napkin:
21 For I feared thee, because thou art an austere man: thou takest up that thou layedst not down, and reapest that thou didst not sow.
22 And he saith unto him, Out of thine own mouth will I judge thee, thou wicked servant. Thou knewest that I was an austere man, taking up that I laid not down, and reaping that I did not sow:
23 Wherefore then gavest not thou my money into the bank, that at my coming I might have required mine own with usury?
24 And he said unto them that stood by, Take from him the pound, and give it to him that hath ten pounds.
25 (And they said unto him, Lord, he hath ten pounds.)
26 For I say unto you, That unto every one which hath shall be given; and from him that hath not, even that he hath shall be taken away from him.
27 But those mine enemies, which would not that I should reign over them, bring hither, and slay them before me.
Let's consider a few things here for a moment. Let's start with verse 15. And it came to pass, that when he was returned. Returned from where? And returned to where? How can the former not be heaven, and the latter not be earth?
Now let's consider verse 27 for a moment as well. But those mine enemies, which would not that I should reign over them, bring hither, and slay them before me.
Why would He need to do that if the entire planet is supposed to literally be ablaze when He returns, burning up everyone on the planet in the process? No mortal person could possibly survive something like that. There is nothing in this parable above remotely showing that the planet will literally go up in flames, literally burning up everyone on the planet in the process, at the 2nd coming of Christ. That is an invention of Amils misunderstanding of some of these Scriptures, such as in 2 Peter 3. And the same is true about Revelation 19, there is not a single place in all of that chapter depicting the entire planet is literally ablaze, burning up everyone on the planet in the process, when Jesus returns.
So when amils argue---which lost people are going to populate the planet after Jesus returns in order for there to be this supposed 1000 years Premil believe in, if according to 2 Peter 3, the entire planet literally goes up in flames, and in the process it literally burns all of the lost up, thus no survivors? Yet the parable above in Luke 19 proves otherwise. Let's don't forget what verse 27 says in Luke 19. You don't slay people who are already dead, who should already be dead if the Amil interpretation of 2 Peter 3 is correct. No, you only slay people who are not even dead yet.