I’m not in a position right now to back this up, but it can be shown quite easily that ‘world’ in the context of this sort of apocalyptic would have been understood as a reference to the ‘world’ that Rome purported to control. Caesar was commonly described as ‘ruler of the world’; and the word oikoumenē, which occurs in Revelation 3:10; 12:9 and 16:14, would naturally be taken to denote the sphere of Rome’s influence (cf. BDAG: ‘the world as administrative unit’). There is no reason, therefore, to suppose that the visions of Revelation encompass events in our own time.