Bolzmann brain moment.
The important part is the paradoxical nature of that a bolzmann brain, as far as the universes lifespan is concerned, is more likely to emerge than a habitable universe.
It’s simple maths. There’s a higher chance that you’re a bolzmann brain than real
I wouldn’t consider it simple math, nor accurate math.
It is a bold statement that makes assumptions about underlying probabilities that are simply impossible to quantify realistically. Even more so as the theory was developed well before computers and human space exploration.
It is an intriguing thought experiment, but not an established scientific theory.
Oh man, why couldn’t my bolzmann brain construct a better reality?
Shh it will all be over in a femtosecond (your structure can not be maintained longer than one instance of sentience before it dissipates back into a cloud of gasses)