Certainly, they did not see Jesus "coming in the clouds of heaven, with power, and great glory;" and most assuredly, that generation did pass away, and many others since, and "all these things" have not been fulfilled.
I know very well, and have very often smiled over the contrivances by which learned Christians have endeavoured to save the credit of this prophecy.

They say that--it is a figurative prophecy relating entirely to the destruction of Jerusalem, which did in fact take place in that generation; that the expressions about the "distress of nations," and "the sea and waves roaring," the "signs in heaven," &c., are merely poetical; and that the shaking of the powers of heaven was merely the shaking and pulling-down the stones of the temple, figuratively called heaven; and that the glorious coming of Jesus "in the clouds of heaven, with power, and great glory," meant merely, that he sent Titus, and the Romans to destroy, Jerusalem, or perhaps might have been an invisible spectator himself.
The reader will easily see, that all this is nonsense.

And the Commentator Grotius, after meddling a great while in this troublesome business, at length ventures to insinuate, that God might have suffered Jesus to be in a mistake about the time of his second coming, and to tell the Apostles what he did, for the sake of keeping up their spirits! But to annihilate the figurative hypothesis of these well-meaning Commentators at once, it will be only necessary to bring forward the testimony following.1.The other Evangelists make an express distinction between the destruction of Jerusalem and the coming of Jesus; and not only so, but represent him as saying, that after that event, (i.e., the destruction of Jerusalem, "in those days," i.e., in the same era in which that event took place,) "the son of man shall come," &c.

Witness for me, Mark, chapter xiii.

24:--"But in those days, after that tribulation, (i.e., the destruction of Jerusalem) shall the sun be darkened, and the moon shall not give her light, and the stars of heaven shall fall, and the powers that are in heaven shall be shaken.