Think of their recent long vacation to Hawaii around Christmas time. Why would they take 15+ days off and travel to Hawaii less than a month before the end of his term in office if they were soon going to be leaving permanently? I'm not even interested in being the president, but if I was in that position I'd have spent as much time as possible in the White House and savored every moment of it.
I've long speculated that the presidency has been a huge disappointment to Obama. He thought he actually accomplished something when he got elected in 2008, and it turned out that he was beholden to Congress for everything he wanted to accomplish. The Democrats jerked him around like a puppet for the two years, then the Republicans ignored him for the last six.
There's some evidence to support his claim that Barack and/or Michelle Obama didn't like living in the White House all that much.