You could probably already make something compelling like a small myst-style game that uses largely static assets with existing tools, taking advantage of being able to render real world environments with high fidelity.
However for more typical games there's still a long way to go. Most of the research focus has been towards applications where existing mesh-based approaches fall short (eg. photogrammetry), but this isn't really the case for modern game development. The existing rendering approaches and hardware have largely been built FOR games and leveraged elsewhere.
Rebuilding the rendering stack around an entirely new technology is a tall order that will take a long time to pay off. That being said, the technology is promising in a number of ways. You even have games like Dreams (2020), which was built using custom splat rendering to great effect (https://www.youtube.com/watch?v=u9KNtnCZDMI).
It will require major changes to the art pipeline. New tools and tech that hasn't existed before. But, that tech is being made right now at a surprisingly fast rate. In a couple years at most it will be possible to make at least an indie-level game with splats. Maybe even with models, animations, audio made to the 80% level with generative AI.
I personally think it's a distraction that we're using so many real-world sources as the source data. But arbitrarily detailed synthetic data, e.g. Nanite, Fractals, etc. can provide much more interesting spaces. I'm kind of surprise that nobody isn't just using examples of Mandelbulbs or whatever as standard data sets for these techniques.
On the whole though, this is really interesting and definitely is an improvement over the much older splat techniques.
