This theory is based on the "Rubber-band theory" in which the universe expands for billions, upon billions, upon billions of years, and then slowly collapses in a similar way. It's all just nonsense, when you think about it. There's no possible way we can figure any of this out in our life time, so what's the point of even trying to think about it?
Regardless, that's how it works, and that's how the Universe ends.
It collapses, and then there's nothing.
That's your theory, right there.