The cosmological 'concept' of parallel universes is less 'unrealistic' than most people realize. It's the perception that counts. What we observe or think we observe, makes something 'real'. It explains why we experience a reality crisis, why we differ from each other in how we perceive things. Social media, nothing less than individuals assessing the world around them from their own virtual bubble, complete the concept of living in multiple universes running parallel to each other. Different bubbles, different choices and paths to follow, tearing apart the fabric of reality as we used to experience and interpret it to a large extent objectively (importance of science and education). So, different outcomes too, as the idea of parallel universes already suggests. Here is one. It’s a good example of what can happen when people perceive things differently (2020 election result), why not change the narrative (Capitol siege) and, consequently, the course of history (restore Trump).

So the question should actually be: “Ask Ethan why we can live in parallel universes while sharing a physical one?”