It is impossible for a Jew to forget Yerushalayim. When he eats, when he prays, when he suffers, when he celebrates, when he weds, when he builds a home, and even when he dreams, he thinks of Yerushalayim. A Yid cannot forget Yerushalayim because he simply can’t live without it.
As the word “korban” itself indicates, when we sacrifice ourselves in order to achieve closeness with the Creator, we are elevating our existence and enabling ourselves to reach the highest of levels of d’veykus b’Elokim possible.
After people experience a loss r’l, as time passes, they eventually forget some of the pain. The hurt eases and people can eventually move on. However, just as Yaakov Avinu could not be consoled after hearing of Yosef’s demise because really Yosef was still alive, the same is true here. The fact that after nearly two thousand years we have not forgotten the Beis Hamikdash and we are still able to cry over its absence, demonstrates that the Beis Hamikdash is still alive.