A few trends have come together, good and bad:
1. Chassis engineers are better at filtering out noise from outside the cabin. Whether they intend it or not, those efforts also affect the volume and character of the engine sound in the cabin.
2. We need to keep fuel economy high and emissions low, but cars are heavy and have lots of drag because people insist on buying unnecessarily tall vehicles and regulations require big frontal areas. So, manufacturers are turning to smaller turbocharged engines. Turbochargers reduce engine noise.
All well and good for a big luxo-barge or something. The problem is when you have a mass-market car that's supposed to have good performance (e.g. VW GTI), or a performance car built on the same platform as a mass-market car (e.g. M3, M5). There's no way to make the engine sound louder in the cabin without letting in other undesirable noise and/or making the engine unacceptably loud on the outside. The easiest way to have engine sound in the cabin is just to simulate it over the speakers.
The car that made simulated engine noise famous is the previous-generation BMW M5, which is a great example. That car was obviously built on the 5-Series, which shared a platform with the 7-Series. It was inherently quiet. Engineers tried all sorts of things -- sound tubes, removing insulation, etc. -- but nothing sounded loud enough and good enough at the same time. That's why the just simulated it.
I don't think anyone would describe that engine as lacking "steam." It has the better part of 600 horsepower. The problem isn't the engine; it's the car around it.