One thing I am sure about is that in 100 years people will look back at us and think, "did they believe that?".
In the last century our ideas of the universe and of subatomic particles have changed enormously. I am sure they will change again in the next. Just think of the changes to our thinking as a result of quantum theory and Einstein.
Whatever I think is hardly likely to be correct, but I am often intrigued by scale. The visible universe is unbelievably huge with probably huge numbers of habitable planets. The subatomic world is incredible. Time is a puzzle. What if all these were linked and whole universes were inside each of us?
It is all a matter of scale. There is no reason whatsoever that universes have to be on the scale we know. Somehow I have the feeling that the macroscopic and microscopic worlds are somehow linked. One thing is certain: we know so little.
Everything remains a mystery.