Changing course when you realize you were wrong has nothing to do with being a clown. Not defending Zuckerberg or the lay off, but for large companies it's always been one of the hardest tasks to predict trends. And many that go under do so because they hold on to old technologies and refuse to admit the world has changed.
If Zuckerberg really changed the whole strategy because he saw VR won't go anywhere and ChatGPT has such potential, changing course drastically would be much better than holding on to old projects due to sunk costs.