- They arise one at a time and continue contemporaneously, (at the same time) for the last beastly power treads them all down. (Dan. 7: 7)
- The first three powers are able to continue on after the last one if judged. (Dan. 7: 12)
- The great powers are in the time of the Lord setting up His rulership under Israel. (Dan. 7: 27)
Okay, so let's consider these.
For the first one, the treading down need not mean that all the kingdoms existed at that point, but rather that the might of the last kingdom was so much greater than all the kingdoms of the past. Besides, if Kingdom 1 conquers Kingdom 2, but Kingdom 3 conquers Kingdom 1, then Kingdom 3 could be said to have conquered Kingdom 2.
For the second point, it need only mean that a vestige of the kingdoms was left over.
For the third, the author of Daniel would have understood the rulership of God over Israel as happening in his time and before - NOT starting in the latter 1900s.