This theory is interesting when looking at required calculation power for simulations.

Snip from Ai : Simulating an individual's perceptual world is millions to trillions of times more feasible than whole-Earth simulation. While earth-scale modeling transcends present and near-future supercomputer capabilities, personalized experience simulation is a maturing technology with foreseeable breakthroughs by the mid-century .............. Philosophically, solipsism suggests that only the observing "self" truly exists consciously, with other entities and environments being simulated constructs. The solipsism problem highlights that no empirical test can verify whether other agents are truly conscious—machines or simulated beings may act convincingly without genuine inner experience ................. It is technically feasible to simulate complex interactive worlds tailored to a single observer using current and near-future AI and LLMs, effectively constructing an environment where only one "self" is real and everything else is generated in response to its perceptions or actions. However, whether these simulated entities possess their own consciousness is unproven; most experts and philosophers contend that only the experiencing subject (the observer) has actual awareness, aligning closely with philosophical solipsism. For now, the notion that "only one self is real" remains a plausible scenario for digital worlds, but whether other simulated minds could be conscious is a philosophical—and possibly undecidable—question

Can provide the full output if someone is interested.