The prophecies where fulfilled and the Jews where unfortunately exiled from their land and dispersed throughout the world, not becase of the physical weekness but as a punishment

The Bible

Also I lifted up my hand against them in the wilderness, to scatter them among the nations and to winnow them in the lands, because they did not keep My statutes, they rejected My laws and desecrated My Sabbaths; and their eyes followed the idols of their fathers.
(Ezekiel 20:23-24)

So He raised His hand in oath to make them fall in the wilderness, to disperse their offspring among the nations and scatter them through the lands.
(Psalms 106:26-27)

“Assyria is the rod of My anger.”
(Isaiah 10:5),

And G-d uprooted them from their land, in anger, wrath and great fury, and He cast them into another land, as they are today.
(Deuteronomy 29:27)

Also I lifted up my hand against them in the wilderness (the Radak and Metzudas David say that after the sin of the spies, G-d decreed all the future exiles), to scatter them among the nations and to winnow them in the lands, because they did not keep My statutes, they rejected My laws and desecrated My Sabbaths; and their eyes followed the idols of their fathers.
(Ezekiel 20:23-24)

 

Talmud

The Prayer Book
“But because of our sins we have been exiled from our land and sent far away from our soil.”
(Musaf Prayer for Holidays)

Rabbi Samson Raphael Hirsch, Rabbi of Frankfurt, Germany (1808-1888)
When we mourn the destruction of the Holy Land, Jerusalem and the Temple, we are not mourning any physical weakness that led to our defeat, but rather we affirm that the destruction was a punishment for our sins, and it is over those sins that we cry. Whatever tragedies befell us, we accept lovingly, knowing that they are the chastisements of a loving Father to induce us to improve our ways.
(Horeb, p. 460)