Salam, Important to not look too much into this topic or start relying on the Imam (a.s) to fall from the sky and fix all of our problems as an Ummah. We have many hadith which mention the coming of Imam Mahdi (a.s) so it is not something we brush underneath the carpet. We also must realise that the coming of the Imam or knowing about him does not necessarily change the way we live our lives.