How Do We Know 5th World Power of Dan 2 is still to come?

The other 4 conquered world governments, and were all spoken of in the scriptures. Yahweh or his people in Bible had some dealings with each world power:

Bablyon - Daniel/Nebuchadnezzer

Medo-Persia - Daniel/Cyrus

Greece - Daniel

Rome - Paul met before Roman Emperor

John in Revelation only mentions one more world power.

Matt. 24:15 speaks of Rome since they are the ones that destroyed Jerusalem in 70 CE. Romans came in 66CE and surrounded the city, but then they left. Now was the time for them to flee. Most did, but many came back after they didn't see anything happening...then they came back in 70CE.