I understand you're saying it's common across several manufacturers, but you overstated it, perhaps for effect, when you said every sporty car.

I remember reading about how the Mazda Miata was tuned to have a nice exhaust note when it first came out, but that isn't what I would call fake engine noise. Conducting sound where and how desired doesn't make it fake.

I also note some of your citations appear to involve random and possibly confused people making guesses on enthusiast forums which are less than an authoritative source.