It's because they skew towards being children more. Apple already has a large children market via the iPad. "Serious games" on daddy's macbook pro and their iPads & apple TVs would further that stronghold. Games are their biggest money maker on the app store as it is, a real serious gaming department with 100-200 employees will pay for itself multiple times over. Apple arcade is another example. Apple Game Studios with first party games like nintendo would probably do better than Apple TV+ does today. They're alllllmost there.