Could the pre-big bang universe be the "end" of our universe and not the beginning?

I agree with this assertion. All evidence points to a “Big Bang,” or simultaneous appearance of the galaxies, being the “beginning” of the universe as we know it. Astronomers using the Hubble Space Telescope have recently found that the universe is expanding up to 9% faster than previously expected. Eventually, and no man knows when this will be, the universe will reach its density capacity and begin to contract again; that is, to begin to regress until it reaches the state that it was in before the Big Bang occurred. This means that the universe will at some point contract to the size of a peach, the same state that the universe was in 13.8 billion years ago before the Big Bang ever happened. This contractual occurrence is explained by a theory called the “Big Crunch,” the opposite of the “Big Bang.”

Based upon what I have read and observed, this mechanism is the very nature of the universe; it is in a perpetual and permanent state of Big Bangs, Big Crunches, and then further Big Bangs, over and over, fostering an endless cycle of the contraction and expansion of the universe. Based on this theory, I am inclined to believe that this endless cycle of “Big Bangs” and “Big Crunches” has been occurring for eons and that the universe that we live in is not the first universe that has ever existed, nor will it be the last, on account of this endless cycle of cosmic contractions and expansions.

So to answer your question directly, yes; the pre-big bang universe is the end of our universe on account that at some point in time, our universe will “crunch” to the state that it was in before the Big Bang, and at some point in time after that event, there will be another Big Bang, and a new universe will be formed.

The following image is a public domain gif that depicts what the Big Crunch might look like.

https://upload.wikimedia.org/wikipedia/commons/f/f4/Big_Crunch.gif