The beast thou sawest was.....
John was seing into the future, The angel told him, at that time (when he was witnessing these events) this beast was, and is not.
Prophesy must be interpreted as it is seen.. Jhn was seeing into the future, Not in his day, So you can not interpret it according to what was going on in his day, it was not the context of the future.
Daniel saw what he thought was one beast concerning the legs and feet and the final beast, when in actuality he saw two beasts, but both were the same (what we know of as rome, or europe)
You could not interpret the fourth beast by looking at daniels day it had not come yet. Same with the revelation interpretation.