Quora Question: Is immortality an illusion since existence will probably collapse in on it self eventually?

Ok, this is not my area, but just a few thoughts, for what it's worth... There are assumptions in your question which may not be true.

Firstly, you are assuming that we, meaning humans on this planet in this time, really understand how all of existence came into being. There is a theory, but it's just a theory until proven, and there could be unknown unknowns that invalidate the theory.

Secondly, even if the first assumption was correct, you are assuming that existence only exists physically. What if physical existence as we perceive it is a projection, a hologram, and that consciousness is the basis from which all things arise, not the other way around? You know, zero point energy and quantum physics and all of that jazz...

Personally, I believe that the illusion of physical material reality being the ultimate foundation of all things will collapse in on itself eventually. Look into the work of Thomas Campbell, he has a Big Toe.

To use that often quoted line from Max Planck, "Science advances one funeral at a time."