His concept of happiness relies on the knowledge of reality. Which makes sense in some ways, assuming that one cares about which reality is important. But what if one doesn't care that much about reality?
He makes a statement that one who plays video games all day is not happy. How does he know? I know plenty of people that aren't excelling by standard metrics in life that are plenty content. Now, they probably aren't the best prepared for certain circumstances that could prevent them from playing video games in the future, such as poverty or war. Those could change the emotional state in someone, I would say they would change the state in almost anyone.
Buddhist monks are perhaps some of the happiest people in the world, they don't have much at all. They focus on non-attachment.
Buddhist Monks Really Are Happier
We do hate to give up control over the most important things in our lives. And viewing happiness as subject to external influence limits our control — not just in the sense that whether you get to live happily might depend on how things go, but also in the sense that what happiness is is partly a matter of how things beyond you are. We might do everything we can to live happily — and have everything it takes on our part to be happy, all the right thoughts and feelings — and yet fall short, even unbeknownst to us.
In my opinion, looking in the wrong place for happiness, and investing considerable effort into things that simply cannot sustain a mental state one way or another, makes it clear that relying heavily on external circumstance simply sets one up for failure. Things are good until your external environment fails, which is almost guaranteed to happen in some form or another. Non-attachment essentially takes the external environment out of the picture.
I am still convinced that happiness is reliant on a mind state. If your mind is out of shape, it is going to get exhausted pretty easily. But certain exercises can wear any body out, just like the mind. Those in better shape will bounce back more easily.
