We're at the point where we need new systems to represent material surfaces better, like leaves glowing from beneath when sun hits them from above, since they're thin enough for light get through. Or imagine putting a flashlight on your skin and seeing your skin glow from the inside around it. Unfortunately a much more complicated scenario than large open rooms and solid flat walls.
Games do simulate subsurface scattering, it's been a staple since the PS4 generation. They currently fake it rather than brute forcing the light paths traveling inside the surface like offline renderers do, but it still works fairly well.
In offline rendering the sky is the limit when it comes to SSS quality, if you have enough compute to throw at it. It's essential for getting skin to look right.
They don't understand or are not aware of the existing systems. UE for example has had a "two-sided" foliage shader model with normal mapping and subsurface scattering for ages.
