It might seem that the prophecies of Daniel 2 and Daniel 7 are about fleshly and earthly kingdoms or empires of man and do not deal with that which is spiritual.
And - dispensationalism in its insistence that everything in scripture is literal has led many to focus on the literal or physical in the prophecy of Revelation 6: 2-6.
While the four horses of Revelation 6: 2-6 do represent physical governments, natural men as political and military leaders, and man made institutions, including the Capital C Churches, the riders upon these natural horses can be seen as supernatural entities. In Daniel 10: 13-21 the angel which was sent to give Daniel the prophecies recorded in Daniel 11 and 12 says the prince of the kingdom of Persia withstood him for twenty-one days. The prince of Grecia is mentioned in Daniel 10: 20. You might think, in a literal way, that these are earthly princes. But they are supernatural beings, fallen angels.
The four riders on the houses of Revelation 6: 2-6 can be fallen angels. The fallen angels are steering the horses, representing natural men, governments and their military forces.
Remember that the common thread in all four horses and riders is conquest, killing, and taking peace from the earth. This is partly why Daniel 7 with its four beast empires fits with the four horses and riders. Each empire has a fallen angel "prince" over it. The parallels between the four empires in Daniel 2 and in Daniel 7 suggest the same fallen angels were over both sets of four. This does not mean that the empires of Daniel 7 are the same as those in Daniel 2.
Nebuchadnezzar’s dream in Daniel 2 about the statute was a prophetic revelation of four empires, now all gone in ancient history. Spiritually, these four empires of Daniel 2 marked the kingdoms of man up to the fourth kingdom or empire, the Roman Empire.
"And in the days of these kings shall the God of heaven set up a kingdom, which shall never be destroyed: and the kingdom shall not be left to other people, but it shall break in pieces and consume all these kingdoms, and it shall stand forever." Daniel 2: 44. But the kingdom of God is not an earthly one. The kingdom of God is within you (Luke 17: 21).
Then, in Daniel 7: 4-7 the four parallel empires mark the time from the rise of the Protestant empires to the time of Christ's return. This does not mean that the Protestant empires were perfect or that they were fully Christian, because the red horse empire of the Soviet Union was anti-Christ and the black horse Nazi empire, though it sometimes claimed to be Christian, was not really Christian. Its just that there was a Christian, mostly Protestant, presence in all four of these beast empires of Daniel 7.
The four statute empires of Daniel 2 marked the time period of the Babylonian exile to the first appearing of Christ and the Diaspora of the multitude of Old Covenant Israel after their rejection of Christ. The Roman empire was still in power at the time of the Diaspora of the multitude of Old Covenant Israel.
The four beast kingdoms of Daniel 7 mark the time from the rise of the British empire until the second appearing of Christ.
The four beast kingdoms of Daniel 7 are the basis for the four horsemen of Revelation 6.
See:
http://www.finalinstructions-logospubco.com/the-four-horsemen.htm
The site above is one of several on the Internet which teach that the four beast kingdoms of Daniel 7 are the basis for the four horses and riders of Revelation 6.
Here is another site on the empires of Daniel 7 being the basis for the four horsemen of Revelation 6:
http://kenraggio.com/KRPN-Four-Beasts-Of-Daniel.html
This site above says "Daniel dreamed of four great kingdoms that necessarily EXIST ON EARTH at the time of the Second Coming of Jesus."
The site also points out that Daniel 7: 12 says that the four beast kingdoms had their dominion taken away, yet they were allowed to exist for a time. With the four empires of Daniel 2 each successive empire replaced the one before it, and the Roman empire continued on into the era of the New Covenant for some time.
"As concerning the rest of the beasts, they had their dominion taken away: yet their lives were prolonged for a season and time.
13. I saw in the night visions, and, behold, one like the Son of man came with the clouds of heaven, and came to the Ancient of days, and they brought him near before him." Daniel 7: 12-13
You have to read the scriptures carefully; they are revelation and not written like a high school textbook, which spells everything out in great detail so the kiddies who are not too sharp can understand it to some extent.