OP -- What has surprised me most, is that lack of difference in overall sound that I have noticed. Is it my ears?
You need a clean sounding reference system to hear the sound difference. All audio systems in the world sounds dirty and distorted. Also, the reviewing cable (or gear) sound noisy and distorted. Therefore, it is harder to hear the sound difference of a noisy cable in noisy system.
My system sounds clean and I live-recorded 4 power cords with my system and the sound difference by cables is clear. Click these times (4:46 JPS), (9:50 Zentara), (14:38 WT v2), (18:53 WTPC) to hear different cables.
All audio systems in the world (except mine, my system sounds like a right speaker) sound like the left speaker in below video which sounds distorted and noisy.
Test your system if it is noisy. Speak anything while your system playing. Alex/WTA