To clarify the lighting point in the article: there are two basic parts to realistic lighting, direct illumination and global illumination.

Direct illumination displays only the "first hit" light that comes directly from light emmiting sources, e.g. the sun or a lamp.

Global illumination (indirect illumination) then adds bounce light that is reflected from the directly lit environment back onto other parts of the environment, e.g. from directly lit walls to other walls. This can also include multiple bounces (indirect to indirect).

When you don't have global illumination, only direct illumination, you get very deep shadows. Anything that isn't directly lit appears perfectly black. Like famously in Doom 3 in 2004. This is why you get so deep shadows in space: you only have the sun as main light source but almost no bounce light from somewhere else.

But even if a game doesn't have any global illumination (bounce lighting), developers in the past were able to avoid unrealistic, perfectly black shadows by always rendering the normal texture colors at a certain minimum brightness. Then the dark shadows merely lower this base brightness to a certain degree rather than appearing completely black.

This was great for a stealth game, because the developers had very clearly defined direct show casting (from emissive lights only) while being able to exactly specify how dark they are compared to the rest of the environment which is directly lit.

But if you introduce realistic global illumination (usually through baked or real-time ray tracing), these tricks don't work anymore. Bounce lighting is very diffuse and it erases the clear distinction between shaded and unshaded areas. Everything lights everything.

I don't think there is a way around this: Either you have clearly defined dark shadows, or your lighting looks nice and realistic. You can't have both.

Possibly a solution is to make the game more stylized, so the missing bounce lighting doesn't stick out negatively. In the past stylization wasn't necessary (Splinter Cell wasn't particularly stylized), because the rest of the graphics weren't very realistic either, so the lack of global illumination wasn't as noticeable.