All this is just "Games haven't(/can't) had their 'Citizen Kane'" all over again. What are you expecting? What would a "Lord of the Rings" of gaming need to do to be "real art" in your (the general you, I'm not really trying to call you out specifically) eyes?

When someone watches a movie, or engages with any other art form, are they "transformed"?

Games are certainly a unique art form, but I reject the idea that they are somehow unable to produce a "shared cultural vocabulary", or that the experience of playing a game can't be discussed to just as rich a level as, say, the experience of watching a movie, or listening to a piece of music. Ultimately, to fully engage in a dialogue about a work of art, you need to experience that work in its intended form, this should be obviously true of music, movies, painting, and games. But to set games apart as somehow less able to be fully discussed is nonsense.