That's not what it is teaching. It means the kingdom of God is spiritual. As such, it has none of the limitations of an earthly kingdom.
The kingdom of God has no borders, it has a king that is eternal, and it can manifest anywhere.
So when the Bible says “flesh and blood cannot inherit the kingdom of God.
What it really is saying is the kingdom of God is spiritual and has no limitations….
The Greek disagrees with you…
The word "kingdom", like the Greek basileia, has regard to sovereignty rather than territory, and to the sphere of its exercise rather than to its extent. Using the word "kingdom" in this sense, and in that which is conveyed in its English termination "dom", which is short for dominion, we note that the former expression, "the Kingdom of heaven", occurs only in Matthew, where we find it thirty-two times (*1).
But in the parallel passages in the other Gospels we find, instead, the expression "the Kingdom of God" (e.g. cp. Matt. 11:11 with Luke 7:28). The explanation of this seeming difference is that the Lord spoke in Aramaic; certainly not in the Greek of the Gospel documents.
Now "heaven" is frequently used by the Figure Metonymy (of the Subject), for God Himself, Whose dwelling is there. See Ps. 73:9. Dan. 4:26, 29. 2Chron. 32:20. Matt. 21:25. Luke 15:21 ("I have sinned against heaven" is thus contrasted with the words "and in thy sight"). John 3:27.
Our suggestion is that in all the passages where the respective expressions occur, identical words were spoken by the Lord, "the Kingdom of heaven"; but when it came to putting them into Greek, Matthew was Divinely guided to retain the figure of speech literally ("heaven"), so as to be in keeping with the special character, design, and scope of his Gospel while, in the other Gospels, the figure was translated as being what it also meant, "the Kingdom of God".
Thus, while the same in a general sense, the two expressions are to be distinguished in their meaning and in their interpretation, as follows :--
The Kingdom (or Sovereignty) of HEAVEN
Has Messiah for its King;
It is from heaven; and under the heavens upon the earth;
It is limited in its scope;
It is political in its sphere;
It is Jewish and exclusive in its character;
It is national in its aspect;
It is the special subject of Old Testament prophecy;
And it is dispensational in its duration.
The Kingdom (or Sovereignty) of GOD
Has God for its Ruler;
It is in heaven, over the earth;
It is unlimited in its scope;
It is moral and spiritual in its sphere;
It is inclusive in its character (embracing the natural and spiritual seeds of Abraham, "the heavenly calling", and the "Church" of the Mystery). Hence,
It is universal in its aspect;
It is (in its wider aspect) the subject of New Testament revelation;
And will be eternal in its duration. ~ Ew Bullinger.