This is largely true in what we might consider more ‘conventional’ comedy. But it is not necessarily true in absurdist, dadaist, or surrealist comedy, where the function is to shatter the audience’s conception of reality the moment they begin to feel that they have grasped it. But of course, those things (dadaism sometimes excepted) are less about levity (which I would consider to be a general light-heartedness and joviality), and more about shocking the viewer into laughing at the outrageous juxtaposition between reality and the object of absurdity which is being made to stand in for reality and to be treated like reality, often (although not always) with straight-faced seriousness by the players.

(It’s BARTZ.)

There are a few games where more avant-garde approaches to comedy have been deployed, and in fact there are a few such moments in Final Fantasy IX (the Crazy Old Man in Lindblum is one). But, by and large, whether it is because of the Japanese origin of western games, general disinterest on the part of devs or audiences, or because of some sort of difficulty inherent to the medium, video games generally eschew such modes of humour. I suspect all three of these potential impediments play a role, in descending order of effect.