Luke 19:44 confirms that "this generation" refers specifically to the generation of Jesus' contemporaries of Jews who rejected Him
(Matt 23:36) Verily I say unto you, All these things shall come upon this generation.
(Luke 17:25) But first must he suffer many things, and be rejected of this generation.
Now, we look at Luke 19:44, and we are told the reason the temple was destroyed with not one stone left standing upon another was because that generation of Jews ("this generation") rejected Christ Jesus:
(Luke 19:44) 44 They will dash you to the ground, you and the children within your walls. They will not leave one stone on another, because you did not recognize the time of God’s coming to you.”
(Matt 23:36) Verily I say unto you, All these things shall come upon this generation.
(Luke 17:25) But first must he suffer many things, and be rejected of this generation.
Now, we look at Luke 19:44, and we are told the reason the temple was destroyed with not one stone left standing upon another was because that generation of Jews ("this generation") rejected Christ Jesus:
(Luke 19:44) 44 They will dash you to the ground, you and the children within your walls. They will not leave one stone on another, because you did not recognize the time of God’s coming to you.”