No matter what anyone does, the universe will end, and reality will stop changing.

Everything dies. Deal with it.

Instead of empowering shithead grifters who promise you a way out, grow trees to create shade for people you will never know. You do that by improving things, not burning limited resources on a conman.

If this outcome is guaranteed, why hasn't it already happened ?

Because we exist inside time, not outside it.

How do you know it hasn't?