Psalm 78:40 "How often they rebelled against him in the wilderness and grieved him in the desert!"

How often we still do! The wandering of the Jews in the desert for forty years should hit home with us, we are in the same boat! We have been saved from the slavery of sin by the promised Messiah, but we have not yet reached the Promised Land of Heaven. What we do in this trek of life is what determines whether we will make it to the Promised Land or not.

God didn't give up on the Israelites, largely because of the intercession of Moses, but He "slew the strongest of them, and laid low the picked men of Israel" (Psalm 78:31); that is, there were many who died in the desert, who never made it to the Promised Land.  In fact, it was largely the next generation that entered Canaan (see Promised Land, The Next Generation).

So while we have been saved by Jesus Christ, and He continues to intercede for us all with the Father, there will be those who don't make it. If we continue to rebel against Him in this wilderness and grieve Him in this desert, it may be that many of our "wicked generation" don't make it, and the promise passes to the next generation.

Sometimes God tolerates one generation for the sake of the next, especially when the first refuses to accept His gifts, and instead rebels against and grieves Him continuously. Maybe let's stop doing that!