The point is that it wasn't a literal coming, God used Rome in her own evil way to do His purpose
Which means there was no coming at all. Rome did what it would have done to rebels, no need for God to have intervened.
Luke 19
41 As he approached Jerusalem and saw the city, he wept over it 42 and said, “If you, even you, had only known on this day what would bring you peace—but now it is hidden from your eyes. 43 The days will come upon you when your enemies will build an embankment against you and encircle you and hem you in on every side. 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.”
A better translation:
Luk 19:41 And when he was come near, he beheld the city, and wept over it,
Luk 19:42 Saying, If thou hadst known, even thou, at least in this thy day, the things which belong unto thy peace! but now they are hid from thine eyes.
Luk 19:43 For the days shall come upon thee, that thine enemies shall cast a trench about thee, and compass thee round, and keep thee in on every side,
Luk 19:44 And shall lay thee even with the ground, and thy children within thee; and they shall not leave in thee one stone upon another; because thou knewest not the time of thy visitation.
"And shall lay thee even with the ground" that has not yet happened.