Actually God said to Noah that he would never "flood" the world again, Not never destroy it. He said the next time he'd destroy the world it would be with fire not water.
Secondly Revelation was talking about the Roman empire and the Nero Caesar, Not modern times. People have been predicting the "end times" for thousands of years and have always been wrong. Revelation thought the "end times" would occur within the lifetime of the apostles.
Thirdly it's common christian belief the WORLD will end during end times. Not just governments. It's common christian belief that the "choosen" will be taken from earth and the sinners "left behind" on earth to live through the end times. Of course revelation itself doesn't say any such thing but that's what they believe.
The ter m fire is used to emphasize permanent destruction. For instance in jerusalem the garbage and waste was consumed by fire and this was used even by the bible as an example of completeness.
Yes. Jerusalum was destroyed in 70 c.e. this was the earthly representation of Gods home and his covenant with the jews. However as fortold they would slay Gods son and a new way of religion would come.
You are confusing the book of daniel with revelation as to world powers that would be destoyed thru time.
Most dont know that their not going to heaven....only 144,000 chosen ones to rule over the new earths inhabitants. They disregard Isiah 65:17 and Psalms 37:11. I dont see the earth inhabited with "meek" ones do you? It must be the second fullfillment of revelation. However this new earths conditons will be like heaven. See revelation 21:4. This is heaven like, so its something to look forward too. Its not here yet , obviously.