The problem is, that the supposed prophecies are so incredibly vague, that like psychic readings or Rorshach tests, you can make them mean almost anything. There are lots of powerful kingdoms, and they rise and fall and defeat each other. That is not prophetic. That is history.
"Next year two powerful lions, one black and one white, will fight each other and one will die while the other emerges victorious."
See how easy it is? I just made a prophecy. This time next year we will no doubt discover that it came true! But only, after the fact, we will realize that the "lions" are not literal lions at all, but actually two baseball teams in the World Series. Or two movies with lions in them up for the Oscars. Or Burger King and McDonald's. Or a hurricane that hits Florida. Or the SDA church vs the JW's. Or the two presidential nominees on the Republican ticket.
To be a real prophecy, it has to be specific, detailed, contain information not known at the time, and should only have one meaning. If should not be open to many different interpretations, based on changing cultural values.
Nowhere in the bible or any other ancient text does it say, "There will be in the 20th century, a country called the United States of America, and it will be the most powerful land in the world for about 100 years, then another country with far more people called China will take over."
There are NO references to incidents in China, the US, the Americas, England, Russia or South Africa in the bible at all. No references to pandas, kangaroos, polar bears, penguins or llamas, either. No references to any of the important discoveries, inventions, medical advances. No, "Relax, we will someday find a cure for leprosy and it will not be bird's blood. People will be able to fly in giant air ships across the oceans in a few hours. Women won't have to give birth in pain because of medicine. And gay people will turn out to be really cool."
Why not? Because the people back then in the Middle East did not know that any of those things would happen.
So, to say that a particular vague passage about a small country and a big country and a bronze something and a kingdom has any specific meaning, you have to fill in a lot of blanks with stuff that only makes sense in retrospect. That hardly counts as a prophecy.