I have been using solid state amplifiers exclusively for years. I also have a new SS amp coming this week. Class A for first 18 watts. So, I don't have much memory for anything in the way of tube amplification.
Someone seemed to imply we were buying high resistance cables but as you point out, we were not paying attention to that. We were paying attention to our ears. Now, at the time of purchase the Fideliums were a huge change in sound compared to the graphene-heavy Cerious speaker cables I was using. A no-brainer.
I tend to think that flat cables carry the signals in a preferential manner as opposed to the very heavily studied round wire science. Can't explain it right now, but between the SC's and PC's it seems to be pleasing these old ears.