As a video game programmer, I can speak to this. For video games, we generally need geometry. Flat planes, things you can collide against, things we can reason about. Gaussian splats work as a bunch of 2D images stuck on top of each other, that in combination look correct. This is great for rendering, but makes it very very difficult/impossible to figure out whether you are inside some geometry or not, because it doesn't have any. it doesn't give you any way to reason about it as solid geometry. So in the end, you have to create the geometry that is the solid surfaces that you will collide against and move around in, and gaussian splats would be independent of that. Once you have all the geometry, its much easier to just render that.
There are tools that will generate geometry from splats, but its generally not very good, and gives messy results. Fixing the messiness is often more work than just re-doing it from scratch. This is another incredibly difficult problem that hasn't been solved particularly well.
That's why Hollywood movies are so expensive. When they have a scene with spider man jumping around in New York, they have to pay a fee to every owner of real estate depicted in the scene.
Worst of all is of course space documentaries, where you can see the whole Earth. The licensing fees are horrendous.
I work in Hollywood and this is or true. We do not have to pay to have buildings in the background. Nor does TV. How would anything be filmed outside if news crews had to pay fees for filming like that? I have made films in NY, London, Paris, Sydney. We can shoot someone walking through a city as long as we have permits for the space. The skyline is free. As is anything else we capture from space we have rights to.
