We don't believe it because it is not possible*. Dajjal, Mahdi, massacre of non Muslims, Judgement day - not possible.
Earth will come to an end and so will civilization - but just not that way. It will be a slower process brought about by ecological factors.
*Don't wish to injure your faith. But it's your belief, not fact. Conflict in the ME is a fact. There is a difference. Let's not discuss this now. Most Indians have not read even the Qu'ran, including Muslims, so we are still co existing. If Muslims in India take religion as seriously as their counterparts in the ME...there will be a lot of fire.