I completely disagree with this. Post-processing can be essential to mark a totally intentional style. Nowadays, movies are still made full of post-processing, take for example 300. Is that too much? It's used to make a difference, like Sin City. The same applies to any VN. This are visual style decisions that can even change from work to work by the same author.
The images in my game, generally have little noticeable post-processing because I wanted it that way. But look at my Banner, noticeable post-processing, perhaps exaggerated for some. If I had opted for that visual style in the game would it be a bad thing? I don't think so...
Every movie uses slight variations of the same process. Give or take with CGI, color correction, etc. Either way, you're correlating films applauded for their visuals to a visually uninspired game. Nor are they even in the same genre. One's a noir, the other is a semi-fictional war movie. But most importantly, they have a reason for looking how they do.
Funny you mention 300. The choice to add slow-motion action sequences objectively hurt the movie. It'd literally be 14 minutes shorter with normal scenes, while also having the benefit of not being corny as fuck. Their choices objectively hurt the movie. Rebel Moon had the same issue, though objectively a worse movie overall. 300 really reminds of that meme "we'll fix it in post". Sin City was made in a visual style. Intentionally.
Look at the examples in the OP. LISC is very, very filtered. That's not a unique look, there's nothing artsy about it. It's just overly bright, overly saturated, and blown out. The fridge and fruit are example A and B. They took the BaD color style and kicked it to 100. It's a shame, because LISC has the elements of a good looking game, too.
Compare it to Summer Heat. The models look normal like LISC, the women are attractive like LISC, they look realistic like LISC. And yet Summer Heat just looks better. It looks more real. The colors make sense. Every character doesn't look like they have a sunburn from the oversaturation.
But as a whole, I think you're misunderstanding me. You can do heavy postwork/editing to cater to a visual style while also making it feel natural or untouched. That's why there's specific job roles for it. SH, Summer's Gone, RoL, etc. all do a really good job of that. You can visibly when a dev uses an action in PS and calls it good. It's unnatural.