There is a rule about Parabola. Everything that Is-Not exists in Parabola. The only thing that is *real* is the Present, hence why we can find the Past in the Parabola (The Waswood) and the Future (Irem).

Irem is specifically the city of the future, as in, it will literally always exist in the future, because Irem is, specifically, "the place where the future goes to wait before it becomes the present".

Irem isn't just a random island, it's basically foundationally metaphysical. Going to the Loom lets us experience all possible futures, and when we "tie knots" (ie: decide our destiny), we choose which path we are specifically going to go down. You can take this option, but if you didn't tie the knot with the Tower Destiny, that Destiny won't happen, because every future is real, we just choose which path we follow.