Theory #3: The spinning top is a metaphor.
The spinning top does not provide an answer for the dream-reality conundrum. Instead, it could be interpreted as “living the dream” or “a dream come true” for Cobb. He was now a free man, absolved of all criminal charges, and reunited with his real (or perceived as real) children. Whether it was reality or a dream did not matter to Cobb anymore (he chose to ignore his totem) because that was not important. What was important was that he was now with his children and they could live as a family again.