Re: [lol perhaps they have increased volume on pop records and such , but seriously LOL no one gets louder than the Heavy metal music dating from 1985 to 1999 LOL so this article may only apply to certain genres really]
You are incorrect - style has nothing to do with it and it is purely a matter of the average power of the signal. Im sure you will find that any metal or hard-rock album prior to 1995 is almost in all cases 'quieter' than about 90% of all mainstream/radio music released since 2001/2002 (And again its nothing to do with how loud you turn it up, that part is purely a matter of prefernce) - but the raw decibel level of the recorded music, and also, for 2 pieces of music with the same average decibel level, one could have plenty of dynamics (higher peaks, quieter lows) and the other could have no variance in the amplitude across the entire song. In this case, the second piece will be fatiguing/bland in the long-term in comparison to the first.
For more information, I highly recommend visiting www.justiceforaudio.org and www.dynamic-range.de