I regard it as a serious spiritual error - despite its being so very common - when it is assumed that the future of this mortal world has been assured by the promises of God and Jesus Christ...
e.g. The idea that eventually the powers of Good must and will prevail on earth... The conviction that The Church must survive and will ultimately thrive.
Such ideas seem to me deeply mistaken, in terms of setting aside the central fact of Man's agency, his freedom on the one hand; and the fact that this mortal world and earth are ultimately ruled by 'entropy', by the powers of chaos - such that all which is formed and organized needs to be sustained by constant consumption of energy and effort; and eventually degeneration, destruction and death will supervene.
This is the nature of this mortal life, and such was recognized by the first Men capable of conceptualizing our basic situation - i.e. the ancient Greeks.
To believe otherwise seems to be one of the earliest and deepest errors that came into Christianity; due, I suppose, to sidelining of the (first and most important) Gospel - i.e. the 'Fourth' Gospel, of 'John'.
But the core message of Christianity is (surely?) the the Messiah brought us the possibility of resurrection to eternal Heavenly life; and he did Not (contrary to much Jewish expectation) come to usher in any kind of paradise upon earth.
Again and again Jesus emphasizes that the things of this world are temporary, but what he brings is - by contrast - permanent (hence necessarily elsewhere).
The clear and simple inference is (surely?) that our mortal lives, the things of this world, and the earth itself; are all impermanent and will come to an end; but that we shall instead (if we want it deeply, and by following Jesus Christ) receive something much better - because everlasting.
I therefore find it quite strange to see Christians speaking as if there is some kind of guarantee that eventually 'things' on this world will be sorted-out; as if there was a divine pendulum that would always swing back from the brink of dissolution; or as if history was a wheel that would cycle back and away from disaster.
Such an impulse to reassure oneself seems like clutching at straws; and worse than this, seems to be pushing against the kind of next-world-rooted attitudes which Jesus is often (in all Gospels) reported to have taught as our proper goal.
Although (ideally) rooted in the next - Christianity acknowledges that the details and sweep of this world - and in particular of our own specific mortal life - is of great and eternal importance; while also being temporary and doomed to destruction.
So the proper Christian attitude is not indifference or hostility to this-mortal-world. Although destruction will eventually overwhelm creation in this world (potentially including All the churches) - and this needs to be accepted; nonetheless we are placed here by God for Good Reasons - and this is the right kind of world for those-reasons.
Therefore, here-and-now; we have choices to make, goals to strive-for, work to do - as best we may