The scripture references to the end of the world are ambiguous. They could apply to any and all times.
But concerning that day or that hour, no one knows, not even the angels in heaven, nor the Son, but only the Father.
And this gospel of the kingdom will be proclaimed throughout the whole world as a testimony to all nations, and then the end will come.
So why then and not now when His Word could be spread so much quicker? Jesus came so long ago, and ever since then, His Word has been debated. And that's the only reason I think of, for the question, "why then?". Is it because we need over 2000 years of processing His coming? If He came now, we wouldn't have the time necessary to prepare for the Second Coming?
IOW, Romans 13:11
Besides this you know the time, that the hour has come for you to wake from sleep. For salvation is nearer to us now than when we first believed.
Yikes! The end is near.