I'm not sure about this harmonic thing. I see good inline 6, V6 engines performinng really well. And some small cars use 3 cylinder engines too.
Because V10 engines are overkill. You can get the same amount of power from a V8 but with much better mpg and reliability. If you pay attention almost all executive car makers have stepped away from V10 engineering.
Mercedes do not feel the need to put a V10 in when they can get power out of a V8. Even Audi and BMW have now dropped the V10 for a V8 as they can get just as much power out of it.
Hi so AMG don't build engines anyway they only tune them.
For the engine to be at harmonic resonance it must be four, eight or sixteen cylinders doubling up to thirty-two and above that. A ten cylinder engine is not harmonic and on a side frequency (harmonic). Basic Physics.
Underpowered, anyone can do that.