Interestingly, the video game industry has regularly grossed more than both the movie industry and the music industry combined[0][1] since at least 2019.
I can't seem to find the relevant article, but esports is now topping viewership of other sporting events (e.g. the SuperBowl). I'm sure eventually, there will be monteization models that follow and it will inevitably be grossing more too.
If anything, it seems like video games are still on the upward trend, and the narrowing is somewhat natural to the maturity of the industry. AAA titles need to gross alot to be profitable, and they stick to well traveled areas most of the time, however one thing I have observed that the video game industry has that the movie industry is lacking is a far more flourishing indie side to the industry[2], such as Yact Club Games or the folks behind Undertale
[0]: https://www.bbc.com/news/technology-46746593
[1]: Mind you, the BBC article is from 2019, you can search for current year and get even wider gaps between the video game industry and the movie / music industry
[2]: With a proper addendum here, that its still, like acting in a movie, ridiculously hard to make it as a indie developer. Still, there is a flourishing of indie game developers