Which probably doesn't have a thing to do with what is being portrayed in Revelation, as prior touched upon in brief.
Scriptures do present spiritual and adverse spiritual "buying and selling" that are not connected to money or external marks whatsoever.
The love of money is the root of all evil. It's amazing how far people will go to say they won't ever have to deal with their dependence on materialism. It's always some "spiritual" issue intellectualized to the point that it has no real meaning in practical life.
We don't see, physically/literally, Jesus' Kingdom NOR do we see Satan's NOR do we see the occupants.
I think you have seriously misunderstood the Kingdom of Heaven.
"And it came to pass afterward, that he went throughout every city and village, preaching and shewing the glad tidings of the kingdom of God: and the twelve were with him" (Luke 8:1).
"Jesus answered and said unto him, Verily, verily, I say unto thee, Except a man be born again, he cannot see the kingdom of God" (John 3:3).
But Jesus also says,
"And when he was demanded of the Pharisees, when the kingdom of God should come, he answered them and said, The kingdom of God cometh not with observation: Neither shall they say, Lo here! or, lo there! for, behold, the kingdom of God is within you" (Luke 17:20-21).
Compare that with:
MT 13:13 Therefore speak I to them in parables: because they seeing see not; and hearing they hear not, neither do they understand.
MT 13:14 And in them is fulfilled the prophecy of Esaias, which saith, By hearing ye shall hear, and shall not understand; and seeing ye shall see, and shall not perceive:
MT 13:15 For this people's heart is waxed gross, and their ears are dull of hearing, and their eyes they have closed; lest at any time they should see with their eyes and hear with their ears, and should understand with their heart, and should be converted, and I should heal them.
MT 13:16 But blessed are your eyes, for they see: and your ears, for they hear.
Jesus told the pharisees the Kingdom would not come with observation for them because they were not really interested in the Kingdom. But for those who are sincere, who hold the values of the Kingdom (i.e. the teachings of Jesus) deep down in their heart, they will see not only see the Kingdom of God, but that kingdom will be expressed through their behavior (John 13:35).
The Kingdom of Heaven is very much something which can be demonstrated and seen in this physical world, but as Jesus suggested, it will only "seen" by those who appreciate it.
This is how it will be with the Mark of the Beast. People who appreciate Jesus' message on greed/materialism will see the Mark for what it is. For people who see no need to challenge their dependence on materialism, they are like the people who hear and see, but do not hear and see. Their heart is "waxed gross"; ever learning and never coming to understand real truth contained in Jesus' teachings.
It's very similar to the parable at the end of the Sermon on the Mount. Jesus talks about two men; one wise and one foolish. Both men heard the sayings of Jesus, but only the wise man obeyed (Matthew 7:26).
A very basic lesson about warnings in the scriptures is that these ARE warnings to DEVILS in the flesh.
I think the reason why your theology (at least regarding prophecy) is so off is because you've left out the cornerstone and, not only that, but you've missed it completely. You say the warnings in the Revelation are meant for devils? No, the opening sentence tells us who the Revelation is meant for.
"The Revelation of Jesus Christ, which God gave unto him, to shew unto his servants things which must shortly come to pass; and he sent and signified it by his angel unto his servant John:" Revelation 1:1
Also notice that the ultimate subject of all the prophecy in the Revelation is Jesus; he is the one being revealed. He is the cornerstone of all of this. Or, as the angel in Revelation 19:10 says, "The testimony of Jesus is the spirit of prophecy".
The testimony of Jesus. I don't see that in your doctrine, smaller.