Curious if people feel the same?
Ear fatigue is caused by higher ordered harmonic distortion that isn't masked by the music or lower ordered harmonics. Its also caused by intermodulations and aliasing in digital gear (which is intermodulations of a different sort). The ear assigns 'harsh and bright' to these distortions and since it uses the higher ordered harmonics to sense sound pressure, is keenly sensitive to their presence even in tiny amounts.
There's plenty of gear out there that can be harsh and bright. Usually the problems show up when you are within 6dB of full power; if your system sounds 'loud' at higher volumes then its an issue. If you are not having problems with these kinds of distortion the system will not sound loud even if it is; IOW you might be surprised to find that you have to yell at someone sitting next to you to be heard.