The tribulation period which is the entire church age, not just the famous seven years in Revelation is a period where God is separating the wheat from the tares.
Romans 9:6 Not as though the word of God hath taken none effect. For they are not all Israel, which are of Israel:
7 Neither, because they are the seed of Abraham, are they all children: but, In Isaac shall thy seed be called.
8 That is, They which are the children of the flesh, these are not the children of God: but the children of the promise are counted for the seed.
There are a lot of people in Israel claiming descent from Abraham, like the Rothschilds, but they are descended from Edom, or they are descended from one of the other children of Abraham other than Isaac. Being descended from the child of the promise is as much about faith as it is about genealogy.
We should not be surprised if many, even the majority of those in Israel are children according to the flesh, God will sort them out over the next seven years.